Need help creating submenu for shutdown timers

So i have the “shortcut” files which triggers a timer, all from 10minutes all the way to 300 minutes. I want to put these on a submenu to my “shutdown” button. I’ve tried addons like advanced launcher, but it doesn’t seem to wanna do what i want at all.

So my question (hopefully a easy one) is; how do i get my kodi to open files from my computer in a submenu category?

example of how it should look:

— Shutdown —
– 10 Min – – 60 Min – – 120 Min – – 180 Min – – 240 Min – – 300 Min – – Stop –

help pls!

thanks in advance