The youth contract is signed before the player 17 years old, and the full-time contract is signed before the player 17 years old and takes effect at the age of 17 years old.

Full-time contracts are common contracts.

Part-time contracts are signed with players when you coach a lower-level league team, that is, less training time. Generally, you can sign the core players in the team full-time so that they can train better.

Only when young players sign a youth training contract will they join the team immediately. If you sign a full-time contract, 17 years old can only arrive.