Else big difference with other prog
Layers are only for visibility not for the geometry!
(a window layer a, glass layer b, you change size window, glass is changed also)
so you must make groups or components for avoid that
Something drawn on a layer is visible on all other layers!!!
Something on calque 0 inside a group on layer b will be visible on layer b even you hide Layer 0
it's not the case for layers different than layer 0

Ideal is drawing something in layer 0, then dispatch it on a other layer

it's for that than some people don't never use layers but just the Onliner!
(only layer0 as you can't kill it)
all is managed by the arborescence and names object
so you must be just well organised and all works perfectly without layers!
No problem of a groups in layer a, other part in layer 0 etc...
only one layer :)

you don't want see something? Select & Right click on the name(s) in the Outliner / hide et voilà :)
Of course you can make anything in the Outliner
group anything, make component anything, move anything etc

So yes "group" first from Moi to Sketchup will be very fine :)
Components will be more complex because they can be also gluying, cutting...