Change template pages

VERY new at all this – but making my way through.
My homepage is static (great), but I would like to have a background image on that page only.
When I add one, it displays on all pages.
When I try to change the template in page attributes of the other pages my only options are:
‘default template’
or
‘full width’
This theme doesn’t even list the front/home page as a page to edit – so I can’t find any option to edit that individually.
I don’t know code.. maybe that’s my problem.. any help would be greatly appreciated!
Thanks.