LetBtbe a standard Brownian motion starting from 0. Define the stopping time

Tb= inf(t ≥0 :Bt=b). Find P(T1< T-1< T2< T-2< T3< T-3) and P(T1< T2< T3< T4< T-1).

I am just beginning to do Brownian motions and don't know where to start. I know the properties of a Brownian motion but am confused by the way this problem is set up.