A reflexive verb needs a small pronoun that refers back to the subject - "myself," "yourself." German uses these far more often than English does, especially for daily routines and emotions.
| ich | mich |
| du | dich |
| er/sie/es | sich |
| wir | uns |
| Sie | sich |
sich is the form you'll see listed in a dictionary for any reflexive verb (e.g. sich freuen) - it's the "default" third-person/formal form, and also what all reflexive verbs are labeled with as their citation form.
| sich duschen | to shower (oneself) |
| sich anziehen | to get dressed |
| sich waschen | to wash (oneself) |
| sich freuen | to be glad/happy |
| sich interessieren (für) | to be interested (in) |
Ich dusche mich um sieben Uhr. (I shower at seven.)
Ich freue mich auf die Reise. (I'm looking forward to the trip.)
Interessierst du dich für Musik?
The reflexive pronoun sits in the normal object slot, after the conjugated verb - it moves with the sentence structure the same way any accusative object would (Lesson 7), it just always matches the subject.
Cross-checked against the Goethe-Institut A1 practice materials.