1-4 are all taken care of. I need to learn more about a roth IRA and what an index fund is. I’m okay with letting $10K sit somewhere for 5-10 years, possibly longer like for retirement.
Read up on Roth IRAs - your future self will thank you! You can open an account anywhere you’d like (Vanguard, Fidelity, Charles Schwab, etc). One thing I’ll mention though: the annual limit is 7K for 2024 (8K if you’re 50+), and you have to have at least that much in income to contribute (i.e., if you only had 5K income for 2024, then that’s your limit).
So, for 10K you’ll have to invest in 2024 and 2025. You also have until tax day to make contributions for the prior year.
Don’t rule out a Roth if you only want to save for 5-10 years. You’re allowed to withdraw the principal (initial 10K) at any time for no penalty/cost, so long as it’s recorded properly with the IRS when you withdraw it.