Don’t get into anything you know nothing about.
Start small and build to big.
‘It sounds like a fun thing to do’ is a good way to lose you financial azz, so have at least 6 months in reserves to start.
Keep brick and mortar space to a minimum, many have unused showroom space, most of it needs to be backroom office and workspace. About 75/25
Like Lucky said above, establish the supplier wholesale links and online business aspect , I would do the web presence first before physical space. Most highly successful shops ship hardware and supplies nationwide on top of local sales…
Recognize it would be a high employee to customer relationship business, so hire right.