Walking floor question

nothing has been said yet, but i have applied for a job at a place that deals with walking floor trailers.
the guy quickly showed me how it operates etc all seems easy. but i got confused when he started mentioning bulkheads etc. now i know if you dont clean them out they will walk all the ■■■■ right through the trailer front bulkhead. thats easy enough.
my question is though when loading pallets or rolls of paper how do you put one on then the next and keep loading without the first one pushing through the front of the trailer.

i would of thought you could stop and start but the controls are right at the side of the trailer. is there a remote normally?