Reflexive verbs conjugate exactly like any other verb, but they carry a reflexive pronoun that changes with the subject: me/m', te/t', se/s', nous, vous, se/s'. Se laver (to wash oneself) becomes je me lave, tu te laves, il se lave, nous nous lavons, vous vous lavez, ils se lavent.
In a negative sentence, ne and pas surround the whole pronoun-plus-verb group: je ne me lave pas. In a question with inversion, the reflexive pronoun stays in front of the verb while subject and verb invert after it: te laves-tu? (are you washing up?).