basic cascade of ui views is:
files <-> lighttable <-> darkroom
you can usually walk the arrows by key accel (enter/escape) or gamepad (x/o).
you can export your work but don't have to save it.
.cfg is saved when you exit darkroom mode or switch to the next image
(backspace/space or L1/R1).
vkdt.db (labels and ratings) is saved when you switch folder or exit vkdt.
colour labels f1-f5
star ratings 1-5
these key accels work in both lighttable mode (on the whole selection) and in darkroom mode (only on the single edited image).
can be customised for each view separately in the gui via settings ->
hotkeys. some keys are special and not in the hotkey system.
f11 goes full screen
ctrl+q quits the application