Hi rigoletto and Grahame,
Directions are given in the imperative mood. These answers are all in the imperative mood, but only one is formal: continui. The formal counterparts of the other verbs are vada, giri, cammini.
The usage of formal/informal is as follows:
Tu = informal, singular
Lei = formal, singular (also translates she)
Voi = informal/formal, plural
Gira and cammina can either belong to:
- the imperative mood of tu (Gira a destra! Turn right! Cammina! Walk!)
- the indicative mood of lui/lei/esso (lei gira a destra, she turns right)
Vai is in the indicative mood (tu vai a destra, io a sinistra, you turn right, I turn left).
Cammini, on the other hand, belongs to:
- the second and third person subjunctive of camminare (che tu cammini, che lei/Lei cammini)
- the imperative mood of Lei (as used in the exercise)
- the indicative mood of tu (tu cammini, io corro, you walk, I run)
Hope this helps!