Nausicaa tells Odysseus to "follow the mules and wagon," walking with her maids toward town, while she leads the way. Once they begin to approach the city, she tells Odysseus to stop and wait in her father's orchard, giving her and her maids time to get to her father's house within town. Nausicaa does not want people in town to see her with Odysseus, because they will assume that she is behaving too boldly and improperly for a young woman. After waiting for some time—enough time for the princess and her maids to get home—Odysseus should walk to the city and ask someone the way to the king's palace. As soon as he reaches the mansion, he should go "quickly, across the hall until [he] reach[es] [her] mother." Nausicaa encourages Odysseus to approach her mother, Arete, and "grasp [her] mother's knees" instead of greeting her father, the king, first. She says that this is the best way to guarantee her parents' help so that he will live to "see the day of [his] return" to his home in Ithaca. The queen must "take [him] to her heart" in order for this to happen.

This question seems to refer to the sixth book of Homer's Odyssey. After leaving Calypso's island, Odysseus has washed ashore in the land of the Phaeacians. The first person he meets is Nausicaa, daughter of Alcinous and Arete, the Phaeacians' king and queen. At lines 251-315, Nausicaa instructs Odysseus on how to approach her father and mother. She gives him directions on how to get to their palace. Nausicaa also tells Odysseus that he should follow behind her so that none of the townspeople will assume that she and Odysseus are linked romantically. She also advises him to first approach Queen Arete, rather than her father, as a suppliant if he has any hope of reaching his native land again:

Stride by him, and throw your arms around my mother’s knees, if you want see the day of your return come quickly and joyfully, no matter how far away your home may be. If you win her favour, you may hope to see your friends, and reach your fine house in your own country. (A.S. Kline translation)

What did Nausicaa instruct Odysseus to do in The Odyssey?

I assume that you are talking about what Nausicca tells Odysseus to do towards the end of Book VI.  At that point, Odysseus has been talking to her and asking her for help.  She agrees to give him food and clothing and things like that and she tells him to come with her to the city.  But she also tells him (and this is the answer I think you are looking for) to stay out in the woods for a while--long enough for her and the rest of the young women to get back to the city.

The reason for this is that she does not want it to look like she has been out in the woods with some strange man.  She does not like the kind of rumors that will arise if people see this.  She tells Odysseus

I am afraid of the gossip and scandal that may be set on foot
against me later on; for the people here are very ill-natured...