I would echo what @[email protected] said about a hire place giving you an introduction on the basics. You should insist that.
Canal & River Trust Boater’s handbook is a a good place to start. They also have a bunch of Youtube videos that’ll prepare you well.
Here are a few random suggestions based on my mistakes and experiences:
don’t try to cover too much distance per day
cruise really slow and you’ll enjoy more
too high boat speed is a recipe for mayhem
locks may seem scary at first, but they are really easy so long you don’t let water in too fast too quickly
help others at the locks and you’ll have nice chats as a bonus
the boat really does not steer unless there is propulsion
try to learn to use steering and propulsion as gently as you can; shouldn’t take much practicing
reverse gently if you beech your boat, and if that doesn’t help, the long pole is your friend (also very useful when your boat ends up stuck across the canal!)
if you are into slow cooking, lamb/beef/vege stew gently bubbling during the day as you cruise is heaven