This happened to me a few times, usually when I was op-upped. Honestly it’s completely fine. A quick smile and a hello, and you can gauge whether the other person is going to be good company or want to keep themselves to themselves.
When I wanted to put the screen up (assuming the other person hasn’t done it first) I would always say something like ‘I am going to put the screen up now, is that ok?’
Really nothing to worry about and no awkwardness at all.