Create a disk in the FreeCAD

Start FreeCAD:

select "Part Design"

Click "Create a new empty document":

Click "Tasks>Create Geometry>Create sketch":

Select XY0Plane, Click OK:

Click "Create a circle in the sketcher":

Click center:

Extend the circle:

Click again at the correct location:

Right click to exit the circle mode.

Click "Task>Close":

Click "Tasks>Sketch tools>Pad":

Set the "Pad parameters>Length" and click "Task>OK":

Click "Set To front view(1)":

Click "Set to axonometric view(0)":