connecting two interfaces

You're going to have to explain a bit more as to what you mean by this.  What do you mean by "moved to"?  Do you mean all users, or certain ones?  Is there a reason you can't define User Start Pages based on user groups, and direct appropriate users to appropriate sites as needed by their group memberships?  If you're talking about some other functionality then it's very unclear based on what you've described here.

Ali Abdulqawi said:

the user when signs in moved to the other interface

You're going to have to explain a bit more as to what you mean by this.  What do you mean by "moved to"?  Do you mean all users, or certain ones?  Is there a reason you can't define User Start Pages based on user groups, and direct appropriate users to appropriate sites as needed by their group memberships?  If you're talking about some other functionality then it's very unclear based on what you've described here.

Ali Abdulqawi said:

the user when signs in moved to the other interface

Mike Schmitt said:

What do you mean by "moved to"?

I've meant when the user inserts his email, and password he will navigate to new interface which is the dashboard. 

Then you'll want to configure user start pages for those users.