Теперь мир для меня просто шум,
Мне безразличны те, кто поучают,
Всегда стараясь указать, как мне себя вести.
I've added "для меня" ("for me") that isn't in the original, but is silently implied and sounds better by meaning and by rhythm. The version without it would be:
Теперь мир - просто шум
I've also omitted "white", as "white noise" is more of a technical term in Russian with little to no meaning for a kid. If a close literal translation is desired, then:
Теперь мир - просто белый шум
that I can't understand - means "make no sense to me", "meaningless", therefore "Бессмысленные"
I can't be bothered - the meaning here is "I don't care", "they mean nothing to me", thus best translating as "Мне безразличны"
with the teachers - "teachers" here are not "instructors", but rather those with an unsolicited advice or guidance. The proper verb here is not "учить", but "поучать".
Always trying - this is straight forward "Всегда стараясь"
to shape - here means "to project their way", essentially like "to tell" or "to show", except not as a suggestion, but rather a demand, although not as strong as "to make". The best equivalent here is "to show" that, as a suggestion, is "показать", which is not applicable here, but, as a demand or forceful influence, is "указать".
the way I act - straight forward "как мне себя вести" that fits nicely by the meaning, feeling and rhythm.
This translation retains the meaning and even emphasizes that the "noise" is the instructions of the unsolicited teachers, that is the substantial connection and transition from the first and the second parts. It is also very literally close and has the proper rhythm making it sound as poetry, but not just word-by-word translation.
Hope this helps :)