How do you brief a substitute without giving them a lecture?

Use two sentences: one about the game, one about the player's role. For a wide player, it might be: 'Their outside defender is playing very high. When we regain it, be ready to attack the space behind; without the ball, recover inside first.' Then ask one question to check understanding: 'What are you looking for when we win it?' That is enough. Do not try to explain the score, shape, opponent, set pieces and every recent mistake in the final 30 seconds. The player is also managing nerves and preparing physically to enter. If there are five important messages, decide which one is most useful now and save the others for a natural stoppage. At U13, a concise brief should help the player notice the game, not make them feel they have an exam before stepping on. Try: 'They are leaving space beside their deepest midfielder. Find that space when we have the ball, and recover goal-side of them when we lose it.' Then ask, 'Where are you looking to receive?' That gives the player one attacking picture and one defensive responsibility.