There is nothing to be confused about unless you don't understand what they're talking about but the post is clear enough.
@OP is not talking about wallet but about software/OS used by Bitcoin ATM. It doesn't work just with electricity as you can guess....
Like ATM used WinXP before, perhaps it still the case
@OP
Check out BitAcces or Generalbytes, if I remember correctly they can provide a "ready to go" solution. It's surely not the only one but if you're new to the niche and are unable to develop your own stuff, perhaps it will be wise to follow this method?