After watching uhTrance and Hoobies NG+ run they defeat Volcano wesker pretty much as soon as the fight starts, i have tried to replicate what they did but am having difficulties doing so, is there a guide i can use to help me learn how to replicate it?

Reference video to show what im talking about (From uhTrance's WR video, fight starts at 1h 35min and 3s)

There is no guide but someone could easily make one. But for now, I can try to explain it. Solo: Chris has to quick turn and climb up, and with good timing shoot the ground as Wesker tries to swing his arm thing. It's weird timing but you can get used to it. Duo: Chris still climbs up but immediately quick turns and jumps off. At the same time, Sheva shoots Wesker's lest shoulder (that's what I find is the best bu you can also shoot the ground or the thing on his back) but once again, timing is everything. Just play around with it and you'll learn audio ques, moment ques and whatever else you feel that you, as the player, can use to make it work the best. Good luck!