Calvs/Abs/Forearms on Perfect Program for Natural Lifters?

I’m following the perfect program for natural lifters off of here and think it’s great. It doesn’t include calves, abs, or forearms in the program. Normally I do what’s typically suggested and work those muscle groups on one of my off days, my only concern with this is it’s a 6 day program so I would ever have a day to let my body rest and recover. I still prefer doing them on my one off day, but want to make sure I grow. Or do you guys think I should just hit them throughout the week and incorporate them into the program?

abs like CT said you do them everyday for 4 to 6 weeks then 2 weeks off and repeat !

calves and forearms you dont need to train them in a specific way, i never train them