How to invite your friends -

Go to your name at the top [demonstrative picture][i.imgur.com]
Select Group[AntiHit] [demonstrative picture][i.imgur.com]
Press the Invite Friends Button [demonstrative picture][i.imgur.com]
Select All & Press Invite [demonstrative picture][i.imgur.com]
After receiving this message press "Ok" [demonstrative picture][i.imgur.com]

Thank you !