Photos won't stay in desktop #1

Hi! I'm not sure how I managed to do this, but on my (beautiful!) new 14-inch MacBook Pro (running Monterey), everything opens up on the main desktop except Photos. Every time I open Photos, it switches to desktop #2 (different wallpaper though the same apps). It's not a huge deal, just really annoying, and I'm not sure how to get Photos back to the main desktop permanently. I've dragged it back, but then when I re-open the MacBook, oops, there it is, once again on desktop #2. (I hope this all makes sense!) How can I get it back to my main desktop and then keep it there? Thanks in advance!