How to make my wifi network private?

Idk how or who set up my wifi, but whoever did made it public. When im home i can only use one thing for wifi at a time. If im on my laptop, i cant use my iphone with wifi. It's annoying. How in the hell do i make it private? Its a netgear router. Please help.

Go to your router's config and set a password.

Open your web browser and type 192.168.1.1 or 192.168.2.1
Your user name and password should be admin but your password could be blank as well.
Look at the wireless tab and you should see security settings. WPA2 is the only choice that should be made as the others are compromised.

Read the instructions for wireless routers here: http://www.justtext.com/wireless-security/wireless-networking-security.html