Please take an air brake course, or at least undertake to thoroughly educate yourself via books or the internet & you tube about air brake systems (not opinions from a forum)......trust me, at this point, you do not know what you do not know about air brakes,..... that may be expensive and scary for you at some point.
(in case you are wondering, I have a class#1 with air brake endorsement DL and have driven otr rigs)