Ok, How to Sync Users between WordPress Sites?
Add sites you would like to sync users with
This is the only required configuration step – please go to Settings > User Sync and switch to the Sites tab. Here you can add as many websites as you want to sync users with.

Configure plugin settings
Right now the plugin settings page look like this. I am trying to keep it as simple as possible but sometimes I add options by customer requests (when I believe it is worth to add).

Sometimes you need to sync only specific user data – for example you may not need to sync the user role changes or specific user meta keys.
In order to configure it – just switch to Fields tab.

Start syncing users
In order to share users between sites you need to select a checkbox of a specific website in the profile settings (or on Add New User page).
No need to select checkboxes in user profiles with Auto Sync option enabled though – the users will be automatically synced with all the sites added in plugin settings.
