How to automate wordpress installation in subdomain

Ok, thanks to m0r7if3, I found the two pieces of information I was looking for: wordpress multisite “Automatically create a new WordPress site in your Network associated with the user that is created.” -> http://www.gravityforms.com/add-ons/user-registration/

Best way to convert two single WordPress sites into Multisite network with shared user base

To me the best way would be to: Leave the ecommerce site intact since it’s where all the important content exist. Enable multisite on ecommerce site. See official documentation: https://codex.wordpress.org/Create_A_Network Export everything on the private site (Tools – Export – All content) Import it on a new site created on the new network.