I am British, how can I become a citizen of Canada, is it easy? Do I have to find a job there first?

Not so straight forward. You can't just go there and expect to become a citizen because you are 'British'. You have to live there for a few years, (it is much easier to become a citizen than say an American citizen) and find a job to sustain you. If you have Canadian ancestry, you could try that way other than that, a few years but not sure how many - probably less than 10yrs