I had Gimp 2.6 and 2.8 and they both had Instrument Panel where buttons were large and below there were explanations/parameters. Now in Gimp 2.10.32 buttons are small and I don’t see where I can choose how Square selection should work - by adding or substracting from selection, etc.
If you keep the pointer over the icon it shows you what it does:
if it doesn’t, something could be interfering with the mouse (security software, screen recorder, and an Nvidia utility IIRC), and you could have other problems elsewhere (can you drag drop layers in the layers list?).
Welcome EditText to Pixls.us
If by Instrument Panel you mean the tool options dialog it should always be open (at least until you know gimp well) so you can see what each tool can do.
If it is not open go to ‘Windows’ > dockable dialogs> and click on tool options. First one in my list