Do I need to, like, do anything special if I reserve for the "Early Bus"?

Yes.  The Early bus allows you to get to the venue early.  Often times it arrives significantly before door time for the event, as well as before other buses arrive.  It may also need to drop off and turn around for another pick-up. 

Riders who reserve the spots with the designation "Early Bus" should be prepared to clear the bus promptly upon arrival at the venue because drivers may be required to make a second trip, and a different bus and driver may provide your return trip.  

This option works great for people who want to get to the lot early and enjoy the scene and scenery, and who don't mind the possibility of transferring to a different BTS bus for the trip home.  

If you are bringing items with you that you will need to transfer to a return bus, you can do so once the return buses arrive at the lot.  Please talk to BTS bus drivers after they park to determine which is the correct bus.  If the return bus has not arrived by the time you are ready to go into the show, you can ask any willing BTS driver to transfer your items for your, although this is always at your own risk.  

On large events, BTS will try to designate a "lounge bus" so that "Early Bus" riders have a home base for their pregame situations.  Ultimately, though, I may be responsible for managing themselves from arrival until departure.