There are some fundemental differences in ideology between UB and Cambium, I would highly suggest that you sit down with the user guide found in the ePMP downloads section. This is explained very well and will most likely answer 99% of your future questions. Welcome to the fold, you'll be glad you came.
More simply:
IF this is NOT a point to point then do not change the AP mode settings. The slaves come set correctly to connect to a AP with the default mode set.
If this IS a PTP link then changing to TDD-PTP will give you GPS sync IF you use a fixed frame (eg 75/25, 50/50, 25/75) If you use flexible frame, then no GPS sync.
Changing to ePTP mode reduces latency but no GPS.
Caveat: Bridge in a Box comes pre-paired to each other. Even though they are slaves, one is set as an AP (master).