Begin with one sheet that holds the major commitments, then choose only what is nearest. Do not turn the plan into minute-by-minute surveillance. Leave room for rest, meals, sleep and movement, and help your teenager see that the plan can change when circumstances do.
Instead of repeatedly asking “Did you study?”, agree on one weekly review: which subject needs a different approach, what made starting difficult, and what support would help at home?
Useful line: “We are organising what can be done; we are not measuring your worth by today’s output.”