Let's proceed in order:
1)The forearms needs only one elastic band,why you should fasten it?just let your arm pass through.
2)Attach the holster via 4 silver coloured rivets on the corners.I used 4 little screws in case i want to detach it.Bunched?You mean you get it folds?(sry im not english so i dont understand really well some technical words)
3)Generally you only need help just for closing the back of your coummerbund.The rest is pretty easy to wear by yourself.Anyway fellows troops always help each other while dressing,dont worry about that.
4)You dont velcro your back armor on the soft parts,just attach the chest and back together through the shoulders and close the gap with some white fabric,close on the sides with some white elastics.
I dont know a precise thread about putting together the gear,i suggest to ook at some build thread for reference.This is how i put mine:
1-undersuit
2-knees
3-boots
4-cummerbund
5-vest
6-belt
7-torso
8-biceps
9-forearms
10-gloves
11-helmet
Hope i understand what you were asking