cams 98 silverado

ok, so im installing new pushrods and rocker arms with some shiny new valve covers. now, i understand how to do the valve lash, alignment all that sort of thing. my question is, how do i turn the motor over to adjust each pair of rocker arms. the engine is still in the truck and all im doing is taking off the old covers, valve train and installing clean new ones. would it be a good idea to leave the engine as is, and take off each rocker arm and pushrod and set in the new rod and then put on the rocker arm and get to zero lash by tightening the nut? would that work? i dont know. i mean my theory is that all im doing is puttin the same thing back, only its new, and roller tipped. but if that would not work, then how can i turn over the motor, im taking the plugs out to let built up pressure out as its turned but how can i turn it? all the videos ive seen online are of motors being built and a corvette with the motor still in but he didnt show how he did it which bummed me out. but please. its rattling my mind and i need to get it done. if your wondering why im replacing them, its because i think the old flat tappet ones are old an starting to make some chitter chatter.

cams 98 silverado

okay so i know how to turn the motor over. i was just thinking way into it and overlooked something. now, heres another thing. the biggest reason im changin out the rockers and pushrods is because of the ticking coming from the front driver cylinder. it sounds like exhaust rocker ticking or chattering. now, when im in reverse and the park brake is on, i got out to listen because thats when my truck is in low rpm. lower than idle in forward gears. and i hear some slight knocking. very slight but evident. at first i was pissed. then i thought. well its coming from that same ticking cylinder. so if the exhuast valve isnt opening or closing exactly as it needs to could it cause that faint knock? its only in reverse. not the trans nor is it the exhaust piping rattling. i made sure sadly it isnt. theres no knocks in idle park or drive just reverse. so can that noise be caused by chattering valvetrain? now my other guess is spark plugs. since i put them in last year but as a noob never gapped them myself but simply believed the manufacturer did it for me as the box said so. so, im putting in new spark plugs, acdelco ones. and gapped at the proper gap. could crappy plugs make a sound in a cylinder from uneven burn?