You may be able to join a club's academy programme if you show the potential to develop to a high level. Academies will usually hold trials and have scouts watching youth players of all ages.
From the age of 9 you're eligible to join an academy run by a league club. If you're under 12, you must live within an hour's travelling distance. If you're aged between 13 and 16, you must be able to travel within 90 minutes.
If an academy takes you on, they'll ask you to sign forms which may be renewed every 1 to 2 years.
At age 16, the club will decide whether to put you on its Youth Training Scheme. You'll be expected to continue with your education at the same.
You could be on this scheme for up to 3 years. If you're making progress, you could be put in the reserves or under-23s team.
At age 19 you may be offered a contract to play for the club, or you may be released into a central pool for other clubs to make you an offer. These may be lower league clubs to the one you've trained with.