diff --git a/app/init.py b/app/init.py
new file mode 100644
index 0000000..19714fd
--- /dev/null
+++ b/app/init.py
@@ -0,0 +1,25 @@
+''' app/init.py '''
+import sys
+from PyQt6.QtWidgets import QApplication
+from .ui.main_window import MainWindow
+from .utils.config import AppConfig
+from cpdctrl.utility.config_file import ConfigFile
+
+
+def run() -> int:
+    """
+    Initializes the application and runs it.
+
+    Returns:
+        int: The exit status code.
+    """
+    app: QApplication = QApplication(sys.argv)
+    AppConfig.initialize()
+    cf = ConfigFile(AppConfig.MAIN_CFG)
+    print(cf.values)
+    cf.set("key", "value")
+
+    window: MainWindow = MainWindow()
+    window.show()
+    cf.save()
+    return sys.exit(app.exec())
diff --git a/app/ui/main_window.py b/app/ui/main_window.py
new file mode 100644
index 0000000..46cda62
--- /dev/null
+++ b/app/ui/main_window.py
@@ -0,0 +1,124 @@
+''' app/ui/main_window.py '''
+from PyQt6.QtCore import Qt
+from PyQt6.QtWidgets import QMainWindow, QWidget, QHBoxLayout, QTextEdit, QLabel
+from ..utils.config import AppConfig
+from .widgets.menubar import MenuBar
+from .widgets.toolbar import ToolBar
+from .widgets.statusbar import StatusBar
+from .widgets.metadata_input import MetadataInput
+from .widgets.plot import Plot
+# from .widgets.treeview import TreeView
+
+
+class MainWindow(QMainWindow):
+    """
+    MainWindow
+
+    Args:
+        QMainWindow (QMainWindow): Inheritance
+    """
+
+    def __init__(self) -> None:
+        """
+        Initialize the Main-Window.
+        """
+        super().__init__()
+        # Window-Settings
+        self.setWindowTitle(AppConfig.APP_NAME)
+        self.setGeometry(100, 100, 800, 600)
+        central_widget = QWidget(self)
+        self.setCentralWidget(central_widget)
+
+        layout = QHBoxLayout(central_widget)
+        central_widget.setLayout(layout)
+
+        # Create Widgets
+        # self.treeview = self.create_treeview()
+        self.editbox = self.create_edit()
+
+        self.create_toolbars()
+
+        # Add Widgets to Window
+        self.setMenuBar(MenuBar(self))
+        self.setStatusBar(StatusBar(self))
+
+        # layout.addWidget(self.treeview)
+        layout.addWidget(self.editbox, stretch=1)
+        layout.addWidget(self.editbox)
+
+        init_elements = [("name1", "val1"), ("name2", "val2")]
+        layout.addWidget(MetadataInput(init_elements))
+        layout.addWidget(Plot())
+
+    def create_toolbars(self) -> None:
+        """
+        Creates and adds the top and right toolbars to the main window.
+        """
+        # Top Toolbar [PyQt6.QtWidgets.QToolBar]
+        self.topbar = ToolBar(self, orientation=Qt.Orientation.Horizontal,
+                              style=Qt.ToolButtonStyle.ToolButtonTextUnderIcon, icon_size=(24, 24))
+
+        # Top Toolbar Buttons
+        self.topbar.add_button(
+            "Open", "resources/assets/icons/windows/imageres-10.ico", self.open_file)
+        self.topbar.add_button(
+            "Save", "resources/assets/icons/windows/shell32-259.ico", self.save_file)
+        self.topbar.add_separator()
+        self.topbar.add_button(
+            "Exit", "resources/assets/icons/windows/shell32-220.ico", self.exit_app)
+
+        # Right Toolbar [PyQt6.QtWidgets.QToolBar]
+        self.rightbar = ToolBar(self, orientation=Qt.Orientation.Vertical,
+                                style=Qt.ToolButtonStyle.ToolButtonIconOnly,
+                                icon_size=(24, 24))
+
+        # Right Toolbar Buttons
+        self.rightbar.add_separator()
+        self.rightbar.add_button(
+            "Privacy", "resources/assets/icons/windows/shell32-167.ico", self.privacy_window)
+        self.rightbar.add_button(
+            "Settings", "resources/assets/icons/windows/shell32-315.ico", self.settings_window)
+
+        self.addToolBar(Qt.ToolBarArea.TopToolBarArea, self.topbar)
+        self.addToolBar(Qt.ToolBarArea.RightToolBarArea, self.rightbar)
+
+    # def create_treeview(self) -> TreeView:
+        """
+        Creates and adds the tree view widget to the main window.
+        """
+        # return TreeView(self)
+
+    def create_edit(self) -> QTextEdit:
+        """
+        Creates and adds the QTextEdit widget to the main window.
+        """
+        return QTextEdit(self)
+
+    def open_file(self) -> None:
+        """
+        Event handler for the "Open" button. Displays the "Open File" dialog.
+        """
+        print("Open")
+
+    def save_file(self) -> None:
+        """
+        Event handler for the "Save" button. Displays the "Save File" dialog.
+        """
+        print("Save")
+
+    def exit_app(self) -> None:
+        """
+        Event handler for the "Exit" button. Closes the application.
+        """
+        self.close()
+
+    def settings_window(self) -> None:
+        """
+        Event handler for the "Settings" button. Displays the "Settings" window.
+        """
+
+    def privacy_window(self) -> None:
+        """
+        Event handler for the "Privacy" button. Displays the "Privacy" window.
+        """
+        print("privacy_window")
diff --git a/app/ui/widgets/metadata_input.py b/app/ui/widgets/metadata_input.py
index e69de29..cbf264d 100644
--- a/app/ui/widgets/metadata_input.py
+++ b/app/ui/widgets/metadata_input.py
@@ -0,0 +1,18 @@
+from PyQt6.QtWidgets import QWidget, QVBoxLayout, QLabel, QLineEdit, QSpacerItem
+
+class MetadataInput(QWidget):
+    def __init__(self, elements: list[tuple[str, str]]=None):
+        super().__init__()
+        self.layout = QVBoxLayout()
+        self.elements = []
+        if elements is not None:
+            for (n, v) in elements:
+                self.addElement(n, v)
+        self.layout.addStretch()
+        self.setLayout(self.layout)
+
+    def addElement(self, name, init_val=""):
+        self.elements.append((name, init_val))
+        self.layout.addWidget(QLabel(name))
+        self.layout.addWidget(QLineEdit(init_val))
+        self.layout.addItem(QSpacerItem(0, 1))
diff --git a/app/ui/widgets/plot.py b/app/ui/widgets/plot.py
index e69de29..ecfc745 100644
--- a/app/ui/widgets/plot.py
+++ b/app/ui/widgets/plot.py
@@ -0,0 +1,19 @@
+import pyqtgraph as pg
+from PyQt6.QtWidgets import QWidget
+
+class Plot(pg.PlotWidget):
+    def __init__(self):
+        super().__init__()
+        self.setBackground("w")
+        self.setTitle("Test")
+        self.setLabel("bottom", "time [s]")
+        self.setLabel("left", "Voltage [V]")
+        self.setLabel("right", "LED [%]")
+        self.showGrid(x=True, y=True)
+        self.time = list(range(10))
+        self.voltage = list(range(10))
+        self.led = list(range(-10))
+        self.line = self.plot(
+            self.time,
+            self.voltage
+        )
diff --git a/app/utils/config.py b/app/utils/config.py
new file mode 100644
index 0000000..eb628b0
--- /dev/null
+++ b/app/utils/config.py
@@ -0,0 +1,25 @@
+''' app/utils/config.py '''
+
+from os import path, environ
+
+
+class AppConfig:
+    """
+    Configuration File
+    """
+    APP_NAME: str = "cpdctrl-gui"
+    CONFIG_DIR: str = path.expanduser("~/.config/cpdctrl")
+    MAIN_CFG: str = ""
+    @classmethod
+    def initialize(cls) -> None:
+        """
+        Perform any necessary initializations here, e.g.:
+        - Loading settings from a file
+        """
+        if 'XDG_CONFIG_HOME' in environ.keys():
+            AppConfig.CONFIG_DIR = path.join(environ["XDG_CONFIG_HOME"], "cpdctrl")
+        AppConfig.MAIN_CFG = path.join(AppConfig.CONFIG_DIR, "cpdctrl-gui.yaml")
+
+
+
+