capsjustes scummvm comes as an .nro that gets launched via hbmenu.
any tutorial to mod/hack the switch should guide you through installing hbmenu. .nros can then be placed in /switch/somename.nro or /switch/somefoldername/somename.nro (more subfolders are possible as well).
You can place the gamefiles wherever you want. Due to a small bug you could have read up on in this thread already, place them anywhere within the /switch/ folder. You can make any amount of subfolders and subfolderlayers you want.
No you dont place them as zip files, you place them as datafiles in extracted folders. A link to a list of datafiles should be in this thread at least twice already - lets make this three times, for people loving the personal service request treatment...
https://wiki.scummvm.org/index.php?title=Datafiles
Also - (if you can) try this with a PC installation of scummvm first, if you have issues - think of doing that as your training wheels to learn how scummvm works.
Also - all of those questions can be considered 'rtfm' (= very basic) so next time try to solve them, or try them at all before asking - please.
Saying thanks - is no substitute for that, because it takes more effort on our end than on yours.