Hello brand,
If you use your .htaccess, then you need a .htaccess in each dedicated folder belonging to the site/product.
If you're still rather new to this, you can safely leave out messing with .htaccess. Totally ignore it, delete it from the folders.
Its really "only" a minor tweak but nothing essential.
robots.txt:
With robots.txt you can include or disallow any robots/spiders from seeing your sites.
Example:
if you get and activate an addon domain your hosting will always create a folder with the name of the addon domain, in the same folder where the subdomains are. (Usually in public_html)
If your site is mysite.com and you would get an addon domain newsite.com, you would find a folder newsite.com
then you would put everything related to newsite.com into that folder.
I hope i answered your questions?
G.
