I know the gist meaning of the song'Because of you' by Kelly Clarkson, but how to understand these sentences's literal & hidden meaning:

I will not break the way you did，You fell so hard，I learned the hard way, to never let it get that far，I never stray too far from the sidewalk，I learned to play on the safe side，So I don't get hurt。
I was so young，You should have known better than to lean on me。

See a translation

If someone 'breaks', it can mean that they lose control of their emotions and it can also mean that they lose their strength (physical, mental or emotional). 'You fell so hard' figuratively means 'you failed'
'to never let it get that far'-to only go to a certain level so as to keep something from happening.
I learned to play on the safe side-I learned to be safe and careful, to not take risks.
lean on me-rely on me, expect me to help you.

Ok. I hope that helps a little. You might try googling "Story behind Because of You" and you might find an article about why the song was written in order to understand it more. :)