Breakdown of Il faut que tu sois calme pour te repérer.
être
to be
tu
you (informal singular)
pour
for
falloir
to be necessary / must (impersonal)
Questions & Answers about Il faut que tu sois calme pour te repérer.
Why is it sois instead of es?
The phrase Il faut que (It is necessary that / You must) always requires the verb that follows it to be in the subjunctive mood. Sois is the subjunctive form of être (to be) for tu.
Why is the pronoun te used right before the infinitive repérer?
The verb here is reflexive: se repérer (to get one's bearings). Even when a reflexive verb is in the infinitive form (like after the preposition pour), you still have to change the reflexive pronoun to match the person you are talking about. Since the subject is tu, the pronoun changes to te.
Does repérer always mean "to get your bearings"?
How could I use this lesson's focus, ne... nulle part (nowhere), with the verb in this sentence?
If you wanted to say "You can't get your bearings anywhere" (literally "nowhere"), you would say Tu ne peux te repérer nulle part. Notice that nulle part goes at the very end of the sentence, after the infinitive verb, rather than hugging the conjugated verb like pas usually does.