If you don't see "more" as an option under "family trees," all I can think is that maybe the UK home page is different from the US one (I think all of us who have responded are in the US). If doing this with a browser through the web site does not work, I would suggest calling tech support and asking.

I don't know how you avoid the app once you have installed it, however, because my recollection is that I tried to do that after installing the app on my laptop and realizing I didn't like it, but it would force me into the app even if I tried to access Ancestry through the browser (that's why I just uninstalled it when I saw I was not going to be happy about using it). If nothing else works, you could uninstall the app, do what you need to do, and then reinstall.