Opening a Roth IRA for myself at 15

I just completed my first week of work.

I get paid next week and I want to open a Roth IRA account for myself at 15 (custodial) but do I have to do it after I get paid or can I do it before? (no reported income though)

I'll be making around $500 next week and I want to put $250 in the account which of course needs to be after I get paid but can I open it before and then put money into it like a week later or do I need to put money into the account as soon as I open it?

I'm planning on putting $500 into the account every month, so can I put money into the account every 2 weeks ($250) or every month ($500)? What should I do before/after all of this?

I have a job, my direct deposit setup, along with my checking and savings account, my debit card, and my ID. I'm 15 so this is all a lot for me personally. I want to open the Roth IRA account to be financially successful in the future. How do I know how much money I'll have in a few years and what else can I do to maximize my financial growth? Thanks for reading!