Create user and site from external script

Hi,
I am trying to create user and site from an external script in same domain & hosting&database

I installed a basic script in root directory and i use a registration form in this script.

and installed wordpress in a subdirectory and activated multisite.

I try to add same username and password in wordpress tables. It’s ok.
I can add users. But i can’t open their blogs.

Are there anyway to do this?

Or anyone have sql query for adding new site?
I can add this to my submit button.