Verbi riflessivi  are a subset of verbs whose action is both carried out and received by the subject. Think of actions like washing yourself, brushing your teeth, combing your hair, getting dressed, etc…
I verbi riflessivi are distinguished by infinitives that end in -si:
                                                                                 lavare              to wash 
                                                                                 lavarsi             to wash oneself

I verbi riflessivi are paired with reflexive pronouns, which distinguish them from other verb forms and let you (and the listener) know that a conjugated verb is reflexive.
The reflexive pronouns are:     

io         mi
tu        ti
lui
lei        si
Lei  ​

noi         ci
voi        vi
 
loro      si

So how do i verbi riflessivi work? It’s actually rather simple! They conjugate exactly like their fellow non-reflexive verbs except for the use of the reflexive pronouns, which express the “to oneself” relationship, and are simply placed in front of the verb.

Nota Bene!

ALL reflexive verbs take essere as the auxiliary (supporting verb) when conjugated in a compound tense like Passato Prossimo.
They follow the same rules as verbs that take essere - they must agree in number and gender with the subject!    

The tables below illustrate the 1st, 2nd, and 3rd  conjugations of some reflexive verbs in Presente Indicativo and Passato Prossimo

PRESENTE INDICATIVO

ALZARSI - to get (oneself) up
mi alzo
ti alzi
si alza
ci alziamo
vi alzate
si alzano

SEDERSI - to sit
mi siedo
ti siedi
si siede
ci sediamo
vi sedete
si siedono

VESTIRSI - to get dressed
mi vesto
ti vesti
si veste
ci vestiamo
vi vestite
si vestono

PASSATO PROSSIMO

ALZARSI - to get (oneself) up
mi sono alzato/a
ti sei alzato/a
si è alzato/a
ci siamo alzati/e
vi siete alzati/e
si sono alzati/e​

SEDERSI - to sit
mi sono seduto/a
ti sei seduto/a
si è seduto/a
ci siamo seduti/e
vi siete seduti/e
si sono seduti/e​

VESTIRSI - to get dressed
mi sono vestito/a
ti sei vestito/a
si è vestito/a
ci siamo vestiti/e
vi siete vestiti/e
si sono vestiti/e​

Esempi/Examples:
            Mi alzo presto per andare a scuola.                       I get up early to go to school.
            Ieri Gina si è alzata tardi.                                            Yesterday, Gina got up late.
            Mi sveglio sempre alle 8:00.                                       I always wake up at 8am.
            Mi siedo un attimo.                                                        I sit down for a moment.
            Gli atleti si vestono in palestra.                                The athletes get dressed in the gym.
​

Reciprocal reflexives
Some verbs among i verbi riflessivi are actually reciprocal reflexives. That is, the action happens between two people “to each other”.  These verbs are formed like reflexive verbs and follow the same rules, but they are only conjugated in plural forms (noi/voi/loro):
Some reciprocal reflexive verbs are:

abbracciarsi          to hug each other
aiutarsi                    to help each other
amarsi                     to love each other
baciarsi                   to kiss each other
conoscersi             to meet each other/ to know each other
vedersi                    to see each other
salutarsi                 to greet each other
sposarsi                 to marry each other.


Ex:    Marco e Anna si sposano a maggio         Marco and Anna are getting married  (are marrying each other) in May