how do i open my phone when its disabled

You cannot if you forgot the passcode.

Forgot or Wrong Passcode

http://support.apple.com/kb/HT1212

Forgot Passcode use recovery mode to restore

http://support.apple.com/kb/HT1808

If you have forgotten the passcode for the lock screen, follow this article:

iOS: Forgotten passcode or device disabled after entering wrong passcode

If this is about the Activation Lock, check these ones:

iCloud: Find My iPhone Activation Lock in iOS 7

iCloud: Troubleshooting Find My iPhone, iPad, iPod touch, or Mac