Changing Font Color from black to white

I can help here.

1. Get your Type tool and change the color of the text from [Black] to [Paper]. That makes the text "disappear" into the white background of the text frame.
2. Then you need to get your Arrow/Selection tool, select the frame with the "disappeared" text and change its fill to [Black]. When the background of the text frame turns black, you'll be able to see the reversed text inside it.

While you can do this in either order, I find it's a lot easier to select the text in the frame first and change it, because when you first change the frame background color it's a lot harder to find where the text actually is. If you change the text color first, it's easy to then select the frame and change its color and get the results you're looking for.

How do I know this? Because I've messed up this way before. Then, I figured out how to fix it. So don't feel like you're not good at this; a lot of us have learned how to use InDesign by error, then trials and travails to fix the problem.

Hope this helps,

Randy