The translation would be;
Marcela learned to use infusions on a trip to Colombia, her grandmother’s homeland.
"Dobles a la derecha." means "Turn to the right.". So yup. It's in command form. If you see sentence that has "May I" or "Can I" in it it's asking. If a sentence has "Do now" It's commanding.
Hope This Helps!
Answer:
I believe that the answer is Usted.
Explanation:
The sentence is a command and therefore could go either way.