Setup MultiSite plugin
Exctract content from downloaded archive into Plugin directory as shown bellow:
Now log in to administration panel, go to Plugins section and activate all plugins.
Configure MultiSite subdomain
MultiSite is capable of creating subdomains for your users. If you own the domain example.com, MultiSite will let your users to create subdomains. In the Plugins section, select MultiSite and enter the domain used for this purpose.
Configure payment system
Go to Plugins section in administration panel, select PayPal Subscription plugin and enter your PayPal email address.
Add critical widgets
Login to admin and add some widgets to desired places of your page:
This widget will give your user website management panel where user can create / manage / delete his websites. While user is not logged in, the login screen will appear.
This is a pricing table. You can configure prices in Plugin section of admin. Add it anywhere you like.
Login / logout / profile
Your users won't be able to logout or see the profile if you don't add appropriate user specific wigets on your website too.