How do i seat a plug 3mm

[bgw1999]

Having problems with sound in Counter strike G.O (a bad buzzing sound) and was told that my ground is bad and should make sure my plugs are properly seated what is this and how do i do this?
Thanks

 

[Karsten75]

seated = pushed in all the way, and correctly. so full contact is made on all relevant connectors and no spurious connections are accidentally made.