Tick anything you already have, in any order. Quests unlock once this is done.
Council courts are often free or a few pounds an hour. Clubs cost more but come with coaching and, more importantly, with people to play against.
Find tennis courts near you2 things left above. Quests are real things you go and do, so they only make sense once you have what you need.
First one waiting: Hit for an hour and keep most balls in