This is probably a lame question but how can you search to see if a topic already exists? Control F works for one page - it is possible to do multiple pages at once? Thank you.
Use the search function on top of this page.
You can use the search on this website. First, though, you have to find it. On a desktop/laptop, look on the upper left for the Rick Steves Europe logo; just next to that in very light type is a magnifying glass and the word "Search." You can filter to look just in the forums. On a phone (and I think it's the same on a tablet, but don't know for sure), look on the top left for three horizontal bars; click on these, and Search is the first option (again, in light type, above the words "About Rick").
I prefer to search using Google. I put in the terms I want (say, "Paris museum pass" without the quotes); an avalanche of results shows up, which I completely ignore. On the upper right, click the gear symbol, and choose "Advanced search." Then, scroll down to "site or domain:" and use "community.ricksteves.com" to just search the forums, or "ricksteves.com" to search the whole website (again, don't use the quotation marks).