While in Capture mode, make sure that you can see video from your source.
Then, press the big, red Record button at the bottom right corner of the window.
Completed recordings can be managed and viewed in Edit mode.
Then, press the big, red Record button at the bottom right corner of the window.
Recording starts when you press this button, and ends when you press the Record button again.
Completed recordings can be managed and viewed in Edit mode.