I have just started to look at facebook marketplace. it has the same problem that facebook does. I can see the entire page then a helpful? box pops up in the middle 3/4 telling me I created a group and what do I want to do in that group.
I guess it created a group for me when I asked a seller about an item. There seems to be no way to eliminate or shrink that box so I can see the main page.
I think there may be useful icons on the top but.. The main page has a big fat toolbar blocking the top 20% of the main screen and the group box as well.
Not sure what is going on. sometimes I can search for 5 minutes before it pops up. other times as soon as I log in it pops up and I have to log out and try again.
BilL D