What you're missing is that PD automatically moves the synced clips to new tracks below your original work area so they won't interfere with any existing timeline content.

To find them, all you need to do is scroll down and then you can select both clips and drag them back to where to want to use them.

BTW if the two clips don't overlap at all, that means PD wasn't able to sync them. If you're sure that they should sync, try trimming one or both of them temporarily to limit the duration PD has to search to find a match. Afterwards you can drag the start/end of each clip to whatever position you want without losing sync.