Please follow the steps below:

1) Run PUBG Mobile app
2) Select your account
3) Enter lobby
4) Select your mode(solo, duo, squad) then begin match making

What are the different modes?

1) Solo: Compete against 99 other players to become the last one standing
2) Duo: Form a team with either your friend or a random partner, and compete to become the last team standing
3) Squad: Form a team with either your three other friends or random members and compete against other teams to become
the last team standing