Use if first conditional and should need to and musn't to talk about healthy habits.

Use the first conditional with if or unless to talk about healthy habits.

Use the modal verbs "should", "need to" or "mustn't" to give advice/instructions for a healthy habits.

Healthy Habits For Children - 1st Conditional & Modal Verbs

healthy-habits-for-children-1st-conditional-modal-verbs

Let's do English ESL general grammar practice. Use if first conditional and should need to and musn't to talk about healthy habits.