How to start a WordPress Multisite over again from scratch

Hi

I’m sure variations of this question have been asked numerous times but I haven’t come across this specific question.

How do I start a WordPress Multisite over again from scratch? I’ve successfully installed wordpress multisite but i had issues when trying to create new sites beyond the first one that came with the install. I kept receiving 404 errors. In set up I used the subdomains over sub directories, and I also enabled the wildcard DNS, however, so I covered those bases in the set-up. The problem is however, I kept receiving 404 errors when trying to set up additional sites. I think the issue may be that I installed my site over the domain option with the “www.” which is recommend not to do.

With what I’ve just said might there be an easier fix to the 404 issue? If the issue is truly the “www.” issue what do I do to start over again from scratch?

Thanks So Much!