You need the warlord perk.
use the perk warlord
Go to your perks and go to War Lord perk and select that then you may buy and put on attachments on your gun. :)
go to attachments for the gun you want it and buy it with cod points
you go onto the class of the gun you want multiple attachments for the you go down to perk 2 and you should see warlord there you have to buy it if you haven't already.
use the perk 'warlord' or 'warlord pro' to get multiple attachments.
You can purchase silencers or SUPPRESSORS in attachments after selecting the gun I believe it is 2000 CoD points
There are many attachments. It just depends which gun it is. Each gun will have its own special attachment. Hope my answer helped.
if you read it on the game it ses you can have to attachments on u primary gun ex. extended mag and red dot
Use the Warlord perk.
Are you playing in the right game mode.
Yes, use the warlord perk (two gun attachments on the primary weapon).
You can have 2 attachments than 1