Ah yes, I fogot about the LN. I'm not entirely sure how all of that works (still need to read up on it quite a bit) but that'll definitely help you with accepting payments.
There is a limit on the LN and I don't think you can put it on a tablet as far as I know so putting it on a windows/linux machine would be necessary (it can of course be a windows/debian/ubuntu tablet instead)...
I know that Pierre Rochard has a great
one-click LN Launcher for Windows and Mac. It will get you set up and running, then you'll have to manually set up channels and send transactions using the cli for now.
If you want a a step by step overview of what the one-click LN Launcher is doing in the background,
this video might help explain. The video description has extra resources for LN as well.
As for setting up the channels and doing a transaction,
this video is super informational (It is using )
These resources aren't for the average shoe store owner. They are more for people who want to be ahead of the game and help implement these stuff FOR the shoe store owner.