Learn Spanish (Spain): ¿Tienes que ducharte ahora?

This is the formula for expressing obligation: tener (conjugated) + que + an infinitive verb. Together, tener que means "to have to". If you just used tienes without que, it would mean you possess something, rather than "you have to do" something.

Why is te attached to the end of duchar?

Duchar is the verb "to shower", and te is the reflexive pronoun meaning "yourself". When a verb is in its infinitive (unchanged) form, like it is after tienes que, you can attach the pronoun directly to the end of it to make one single word: ducharte.

Does the attached pronoun have to match the person I'm talking to?

Yes! Even though the verb duchar is in the infinitive, the pronoun still has to match the subject. Because you are asking "Do you have to...", you use the informal "you" pronoun te. If you were saying "I have to shower", it would be Tengo que ducharme.

Where is the word for "Do" in the Spanish question?

Spanish doesn't use helper words like "do" or "does" to ask questions. Instead, you just take the normal statement (Tienes que ducharte ahora, meaning "You have to shower now") and add question marks and a questioning tone of voice.