With the Paint tool selected, click in the timeline and drag to add an event using the track's active clip. The longer you drag, the more times the loop will be repeated (one-shots and Beatmapped tracks do not repeat). Dragging across track boundaries creates events on multiple tracks.

To change the track's active clip, click the Paint Clip Selector button in the track header and choose a new clip from the menu:

Repetitions in the loop are denoted by the black indentations in the top and bottom borders of the event.

Right-click with the Paint Tool to erase events.

Hold Ctrl and click with the Paint tool to paint the entire media file as an event.

When you are ready to continue, click the Next button.