Week 1, 3-day induction at training centre (TC), then 2 day PTS, usually Tyseley depot.
Week 2 & 3 rules course (TC).
In local depot, rules exam with manager - then with local conductor instructors (aka minders) weeks 4,5,6,7 learning routes and traction - number of weeks dependant on depot & routes signed.
Weeks 8 & 9... 2-week retail course (TC)
More route learning, train working experience for several weeks with conductor instructors
Final signoff, first with local depot manager - 2 rideout days & signoff with area manager & ops standards.
So... 3 months... ish. Factor in extra time due to Covid.
Very few fail, if you're sensible enough to ask for advice on here, you probably nothing to worry about.