Taking apart my Dboys AK

[ProfJosh_]

I'm trying to take apart my dboys AKS74U to replace the bucking and nub but having some problems with disassembly, so far I have the muzzle, the bolt lever, selector switch/lever, and the spring holding the top dust cover off. Not sure where to go from here to get to the bucking and nub as I'm new to this and I can't find a video with the exact model of the gun to follow..

[Samurai]

[ProfJosh_]

Followed this video but it is a bit different as i cant get the front outer barrel assembly off.

[Samurai]

Can be a grub screw under the rear sight's movable part.