Recordings can be edited by first clicking on the video under TV > Recordings, followed by the Edit option.
To trim the beginning or end of the recording, click and drag the outer left or right-hand edge of the timeline.
To cut out a region, place the time where ever you want to begin cutting from, and click the scissors button. Do it again where you want to resume. Then toggle the tick state from keep (green tick) to delete (red x) by clicking the green tick. Once a cut is made you can tweak it by grabbing the edges and moving them around. If you change your mind, use the Undo button.
When you're done making edits, clicks the Save button.
A copy of the video will be saved so you can check and make sure you're happy with it.