How do I install the scope? (Tom Clancy's Rainbow Six: Siege)

My default is on the number 4

You buy an operator, go into its settings, choose a weapon and there you already buy modules

SHooTER32RUS
Thank you very much

dsom
What are you talking about? In my opinion, there are no double sights in the game, except for a sniper rifle, and even then there by default on SCM

Termite and Ash have a 2.5x scope in unlocks