Where's my Applications folder?

PS I just had a thought, IF i could install Betterbird (not sure I can as it seemed quite complex according to the dev), that will probably resolve this issue. I am going to open a new thread asking for any Betterbird users to advise as I think that could be a quicker solution. Just scared about installing and backing up/losing accounts and data. It took me WEEKS to get my mail into TB from Mac Mail! Here’s the new thread: Any Betterbird users here?