How do you mirror/clone more then 3 phones

[Loweredchevy88]

I would like to hook up 4 or 5 phones together, when I do something one phone I want it to do it on other phones. I'm sorry for my stupid questions I'm not much of a tech guy. I found a phone of a guy that has 1 phone hooked up to 10 other phones and that 1 phone controls the 10 if anyone can help me do this I would love to know how