Financial advice for 23F just starting career

So I work in the government sector and earn about 60K right now. I do some extra side work and earn let's say 10k per month. So, totally about 70K a month. Now, I belong to a very lower middle class and even this amount is quite huge for us. My family lives frugally as such, we don't have an AC or something.

Now firstly, I would want to improve my family's lifestyle like getting an AC and better nutritious food, etc. I would really appreciate some insights on this and how to save and invest money. No generational wealth and no property on our names alright. We don't have any loans so far. I would have to just help a bit with setting up my brother's business - which ofc be promised he would return in due time (but I'm not really sure if I should do that).

I don't really want to take advice from my dad, who himself out us up into this situation due to his bad decisions. Would be great if I could get some real talk :) thanks!

Edit: It's not a business. So I edited the word. I'm skilled in something and people I know closely are happy to pay me a small amount for that work.