Enable usb debugging in developer options (tap build in about to activate developer options)
go to dial type *#0808#, choose DM+Modem+ADB
Connect the phone to pc using usb cable
Wait for drivers to be installed
Open chimera tool
Click Unlock, Wait Till Finish, Phone Reboots
Turn off phone, insert other carrier simcard.
Turn on phone, now wait for signal.
go to dial type *#0808#, choose MTP+ADB
Go to Developer Options, uncheck enable developer options
(Note: You can use this steps if you are using Z3X or Octopus Box)