I’m trying to append a material from another file. I press SHIFT+F1, browse to the source file, but when I click on it nothing happens, it doesn’t expand out into the subfolders. Also, I’m still struggling to get used to the new 2.8 interface and as such can’t work out how to get back to the modeling screen once the append doesn’t work, so I just end up dead in the water and have to restart the programme.
Pressing SHIFT-F1 doesn’t do Append. It’s the shortcut for opening the file browser.
To do an append select the append from the file menu:
As to your second problem, when you use SHIFT+F1 thru to SHIFT+F12 they are all shortcuts to the various editor windows you can have. Whatever window in blender you have your mouse over will automatically be converted to that type the short cut represents. It can be changed by selecting the icon at the top left [ I took this screen grab from the 3D Viewport so the icon top left, in the red box, shows this icon ] or by using another shortcut to get back to where you were.
It looks like this (also notice that the shortcut is written adjacent to the label):
Hope that helps,