Hello, welcome!
No, these are not stupid questions at all. I remember the first time I set up an IRA.
Think of the Roth IRA like a bucket. Whatever you put in this bucket is protected from taxation. But you still have to decide what you put in the bucket. By default, when you contribute to a Roth IRA by hitting the "contribute" button, the broker will put your money in money market funds or cash equivalents, until you decide what to do with it. You will get some interest on these money market funds; if you check your transaction history, most likely you'll see a few cents in interest or something like that.
But at some point, you will want to invest these funds in something else. Those can be stock ETFs, or bond ETFs, for example. Meanwhile, if you haven't decided yet, its perfectly OK to have your money sitting in money market funds. The most important thing is to get your contributions into that bucket; once they are there, you have all the time in the world to decide how to invest them.