Clips in the bins (top-left) can be used multiple times and trimmed on the timeline. Drag them to the timeline at the desired spot or right-click the bin clip and use one of the PLACE choices.
If a trimmed clip on the timeline is dragged back to the bin it will be saved with the trim intact and given an incremental # (1, 2, etc) while not altering the original clip.
Clips also can be trimmed in the bin, using the SET START and SET END buttons under preview. Then click the ADD button to drop them into the sequence at the cursor position. In that case, that bin clip will always retain the trim.
Rename clips in the bin via a right-click.