Exegesis:

kai hōs etelesan panta ta kata ton nomon kuriou lit. ‘and when they had accomplished all the things (that were) according to the law of the Lord, i.e. all the requirements of the law of the Lord.’

teleō ‘to bring to an end,’ ‘to accomplish,’ ‘to fulfil.’

epestrepsan eis tēn Galilaian eis polin heautōn Nazareth ‘they returned to Galilee, to their own city, Nazareth,’ same construction and order as in v. 4.

epistrephō here ‘to turn back.’

Translation:

They, or, ‘the parents (or, the father and mother) of the child.’

Had performed everything, or, ‘had done everything (or, all thing they had to do).’

According to the law of the Lord, cf. on v. 22, and, for the meaning of the possessive construction, on v. 23.

Their own city, Nazareth, or, clarifying the possessive pronoun, ‘the place where they lived, that-is the city N.’ (Bahasa Indonesia RC), or, “their home town of N” (Good News Translation).

Quoted with permission from Reiling, J. and Swellengrebel, J.L. A Handbook on the Gospel of Luke. (UBS Handbook Series). New York: UBS, 1971. For this and other handbooks for translators see here . Make sure to also consult the Handbook on the Gospel of Mark for parallel or similar verses.