I also use fidelity. But yeah your money is sitting in dollars until you specify investments for it.
Put it in an index fund, or in a stock you like. Its still like the normal market, the ROTH IRA just has a yearly limit because of tax benefits you will get when you turn 59.
But you should always max the 12k in it (or 6k if single) first every year. Then start putting money in your taxable investment account.
The safest investment is something like a market tracking index fund. Those tracking back a century never lose over TIME. They always return as long as you dont fukk with them.
VTI is a good one. Slow burn, earnings over time that will beat any high yield savings account by far.