First, I moved your post in the GSX section, since you posted it in the wrong (General) section.
As explained in the manual, passengers will be visible ONLY if:
- If your parking spot is a gate with a jetway, in order to see passengers the jetway MUST be SODE, either supplied by the scenery itself, or replaced by GSX. In default airports, default jetways are automatically replaced by GSX, but on 3rd party airports, you must replace them manually, as explained in the manual and on several tutorials in the GSX forum.
- If your parking doesn't have a jetway, your airplane MUST be correctly configured for GSX so it can call Passenger Stairs, and a Bus will appear.