I used Kdenlive to make a new Numbas demo video.

I was pleased with how easy it was.

• Wrote a script, using the old video and the text from the Numbas front page.

• Did some screen recordings to cover each of the bits.

• Made 1920×1080 images using the drawings from the front page.

• Recorded the script in gnome-sound-recorder.

• Dragged all the files into kdenlive.

• Cut out just the bits I wanted from the videos and the sound by making zones: play a clip, press I to set the start point, and O to set the end point, then Ctrl-I to save that as a zone.

• Eventually realised V inserts the selected zone into the timeline.

• Dragging things around on the timeline is easy. The move tool with M shifts a contiguous block of things around to make space.

• Worked out that you can trim bits by dragging their sides in the timeline, and add fades or wipes by clicking the dots that appear in the corners of a clip.