Its timing based, meaning as soon as 2 wrestlers "lock up", meaning as soon as you see your wrestler touch the other guys shoulders in the lock up animation, you press up, left, right or down on the dpad and the weak grapple button.
As the match goes on you upgrade to the medium grapple instead and eventually heavy etc. You want to wear out your opponent. As the match goes on and your stamina goes down, the timing changes, meaning you have to adapt constantly
It is essential that you do not spam, as that will always result in getting your ass beat, the game basically detects if you are mashing. Just press up+weak grapple once as soon as they lock up and hope you were faster, not 2 times or more.
Strikes wear your opponent down, and if you hold Select you get to regain some of your stamina.
There is a ton more to the game, but those are just the basics, timing is key, mashing buttons even more than once is insta loss
