Using Special attack button (attack3 by default) you can shoot decoy , flash, smoke nades based on weapon slot like:
Primary Slot = Decoy Nade
Secondary Slot = Flash Nade
Melee Slot = Smoke Nade
Cvars TFGO_enabled 1 Def 1 "Enable TFGO nades?" TFGO_smoke_color_mode 0 Def 0, 0 grey, 1 random, 2 teamcolor TFGO_ammo 6 Def 6 , number of TFGONades aviable TFGO_dist 1000.0 def 1000.0, Distance from Flashbang to get flashed