I need to get my filter/pump going but having trouble

Galleria 18x33x52 (15 000 gal)

Just filled the pool and trying to get pump/filter going have a pool frog set up as well. NO CARTRIDGE inserted yet !

have a Best Choice Products Pro Above Ground Swimming Pool Pump System 4500GPH 19" Sand Filter w/ 1.0HP

do i have to wait until filter is filled with water ? The initial first second water is coming out for backwash and then it dies . NO reading on pressure gauge

Manual is for the birds !

no idea where to deplead either. primed the pump

Afraid I will burn up pump so shut everything off after no pressure detected !!!!

ANY help appreciated