How do I become a psychologist in the UK?

I’ve done my research but it’s so unclear. I’m currently doing my BSc psychology. I’ll be in my final year in September and I’m thinking of what to do for masters already.

Does it go like this?

UNDERGRAD + MASTERS = Psychologist

Or

UNDERGRAD + MASTERS + PHD = psychologist??!

Whats the certificate thing about??? Do u get that after masters or right after ur undergrad?

I wanna do sth hospital related so within the nhs. I’ve been looking at psychology wellbeing practitioner jobs but are there any other jobs that are quite similar?