Hey Guys... I'm at rank 32 now, but I REALLY don't know about the squad.. Not one bit : )

Can some of you guys that "do" know about HOW TO join squad. Please tell me, from the 1st step please
I have my friend that has squad too, and he has invited me to join his Game and play with him sometimes but i don't really have some kinda Letters in front of my name
How do I use his squad name in front of my name : )

go to operation status then add ur clan tag

the guy above pretty much spelt it out its also not squad name its as mentioned clan tag