hi, i need to have 4 site with different content, modules, template but with the user share using community builder. how can i do it? pls i have try for 10 hours with a friend and none

after hours we have share user between 2 slave site, but no master-slave...

The sharing of users is decided when creating the slave site and can not be decided later after that you created the slave site.

I suppose that if you had problem to share the users with the master, this is because you started to create the slave site without sharing the users.
If this is the case, you have to delete the slave site and rebuild it.
It is not to modify a website that is already created to convert the users in "sharing users".

So verify the JMS Template rule where you have to
- select the template site = "master DB"
- A least enter a new table prefix
- In the shared tabs, select the joomla user sharing

I also suggest to also pre-fill the "domain name" and the "deploy folder".
In example
- domain name = {site_url}/multisites/{site_id}
- deploy folder = {site_dir}

The rule is similar to the "replicMaster" one that you can find illustrated in the tutorial video 0.d and also explained in the forum.
The additional thing is to select that you want to share the joomla user and in your case, also the Community Builder users. See the "share tab".

Once you have created the JMS Template rule, you can use it to build the slave site.

we want the master site on 1 database, slave site in a 2nd database
i attach 8 screen of the configuration, these are all test.
tell me what we wrong. thanks

imageshack.us/g/263/screen1th.jpg/

In the template rule (replicMaster) you forgotten to put a new DB prefix (mandatory field).
In addition, you don't show the "share tab" where you have to specify the sharing

Finally, the error message that you have when creating the slave site is the very documented on "Command denied to the user".
As mentioned plenty of time, this is a problem of permission on your MySQL user.
See tutorial video 0.b slide 34 on how to grant the MySQL user with PHPMyAdmin when you don't have the permission provided by your cPanel.
Or contact your hosting provider to increase your MySQL user privileges.

we have replicate the master site.
now, can i uninstall jms on slave site?
I can not install extensions on the slave site, tells me that I must install it before on the master even I already did it

thanks