Help me finish this before xmas! (Brake issues!)

Anyone fimiliar with tektro R725? This rear brake is a pain in the ass since it’s the brake system mounted right behind the bottom bracket.

Im redoing the cables and I after pulling as hard as I can on the cable through the frame and tightening the little joint I cant get any good pressure so that the pads will him the wheel.

Any help much appreciated!!

Were the pads clamped to the wheel before tightening cable?
Also need to back off barrel adjuster before tightening to adjust
pad distance.