Contributions to an IRA are limited by your
federal government. At your age, the limit should be $5,500.
The choice between a standard (aka "traditional") and Roth IRA is based on assumptions you have to make about taxes. I did not see an explanation in this thread why you chose Roth over traditional. (Keep in mind that you can open both, and contribute up to $5,500
total split between them. You may want to open a traditional account with another $10 and do some research on which you think you'll want to contribute to going forward.)
VTSAX is a "level" of Vanguard's Total Stock Market index fund. There's also
VTSMX with a $3000 minimum, or you can just buy the
VTI ETF for now, if you cannot hit those minimums. There's really no downside to the ETF, and some really prefer it over the mutual funds. They are reasonably equivalent in most important ways.
Additionally, a solo 401(k) is a very nice option for the self-employed. I have one, and it increases my contribution limit massively. Where as your IRA has a limit of $5,500, I can put $18,500 into the 401(k) as as "employee" but I can also put additional funds as the "employer" with a much, much higher limit.