1. Launch FinalCut Pro X
2. Right click on the Event Library (left side), and choose New Event, and name the Event.
3. Click on ‘Import Files’ to the right and navigate to the clip file you want to use. Double click to import it.
4. To import the other file, right click on the Event and click ‘Import Files…’ and navigate to the file and double click it.
5. When you have all the clips you want to use in the Event, right click on one of them and select ‘New Compound Clip’ and name the Compound Clip.
6. Click on the Compound Clip and drag the other clips to it to add them to the timeline of the Compound Clip.
7. Make sure the start and end times of all the clips are lined up properly. The Compound Clip can be formatted however you want.