I suppose you mean this from the Yahoo site:
Attention: Starting December 14, 2019 Yahoo Groups will no longer host user created content on its sites.
IMO, that is no big loss. Yahoo Groups is one of the worst forums on the Internet.
IAC, I'm not sure how good of a place that was to learn UI Browser. I never use it myself.
IMO, the owner of UI Browser needs to open up his own forum, like a Discourse forum, to properly support his product. But being a one-man shop, he may not have the resources.
So, at this point I would follow the instructions on the UI Browser support page:
For detailed instructions and more information about using UI Browser, launch UI Browser and choose Help > UI Browser Help. If you have questions that aren't answered in the Help book or on this website, send email to us at firstname.lastname@example.org.
I have found UI Browser to be one of those tools, which has a very unique UI, which is best learned by experimentation, trial and error.
So, I'd do just that, and if you can't figure out how to do something, send an email to email@example.com asking for help.
Sorry I can't be more helpful.