Être sorti means to get out:

Je suis sorti de la maison – I got out of the house.

Je suis sorti avec Marcel – I dated Marcel.

Avoir sorti means to put something outside:

J’ai sorti les poubelles – I took the trash out.

There are a few verbs that are composed with the verb être in the compound tenses (passé composé, plus-que-parfait, futur antérieur…).

You can memorise the most basic ones with the following mnemonic rule

MRS DR VANDERTRAMPP

Monter, Rester, Sortir, Devenir, Retourner, Venir, Aller, Naître,
Descendre, Entrer, Rentrer, Tomber, Revenir, Arriver, Mourir, Passer,
Partir.

Monter –> monté (went up)

Retourner –> retourné (returned)

Sortir –> sorti (went out)

Venir –> venu (came)

Arriver –> arrivé (arrived)

Naître –> né (was born)

Descendre –> descendu (went down)

Entrer –> entré (entered)
Rester –> resté (stayed)

Tomber –> tombé (fell)

Rentrer –> rentré (went back in)

Aller –> allé (went)

Mourir –> mort (died)

Partir –> parti (left)

Passer –> passé (pass)

See here:

http://bookshelf.mml.ox.ac.uk/2015/05/06/fun-with-grammar-heres-to-you-mrs-vandertramp/

Another mnemonic rule is given here (the so-called La Maison d’être):

https://www.cliffsnotes.com/study-guides/french/french-i/french-i-the-passe-compose/the-passe-compose-with-etre

These are all intransitive verbs (that is, they have no direct object) that communicate a certain kind of movement.

(Note that the inverse is not necessarily true. E.g. Courir meaning run is conjugated with avoir. Also, e.g., voler (fly), rouler (roll), nager (swim), marcher (walk), sauter (jump). Therefore il a couru, nous avons nagé and so on.)

Normally all these verbs (MRSDRVANDERTRAMPP and their compounds-parvenir, repartir, remonter, redescendre, ressortir, etc.) are conjugated with être. However, the following verbs are a bit tricky.

Monter, Sortir, Retourner, Descendre, Passer, Rentrer

These can be used transitively (with a direct object), and when this happens, these verbs need avoir as the helping verb. In addition, there is a slight change in meaning.

Elle est sortie. – She went out.

Elle a sorti la voiture – She took the car out.

For more you may consult the following page

https://www.thoughtco.com/etre-verbs-french-auxiliary-verbs-1368843

Être is also used to form the compound tenses of Reflexive Verbs and the Passive Voice of Transitive Verbs. E.g.

Je me suis promené(e). Le pont a été démoli. La porte était ouverte par le concierge.

Monter and descendre also take avoir in such expressions as:

Ils ont monté l’escalier. J’ai descendu la rue.

Note also that for a few verbs like demeurer, changer, grandir, vieillir (respectively, change, stay/remain, grow, pass, grow old), there is a difference in meaning between expressing action (conjugation with avoir) and state (être). Cf.,

Il y a demeuré pour soigner sa mère (action).

Il est demeuré insensible à nos prières (state).

Elle a beaucoup grandi au collège (action).

Comme elle est grandie (= Quelle grande elle est) (state).

La journée avait passé tranquillement (action: had passed).

Le danger était passé (state: had passed-was past).

Above may be used as guidelines for further reading.

See also the relevant discussion here

Dr and Mrs Vandertrampp

(thanks @jlliagre for pointing me out this discussion)