Don't be embarrassed about that. Most of us long-time users have learned almost everything through stumbling around, finally giving up and posting questions here, and (hopefully) finding the answers.
KM is so deep that I doubt that even @peternlewis (the author) remembers everything it can or can't do! (Maybe that's a touch of hyperbole - then again, maybe not...)
I am noticing a considerable lag in switching desktops via a keystroke (^←). It seems that the first attempt to switch desktops works normally, then subsequent ones are delayed. If I wait an about 3 seconds between keystrokes it works normally. Seems like there is a delay after switching.
I recently upgraded to 15.4.1 but I'm not sure that is causing the delay.