configur freepbx to working with goip4 gateway

I have freepbx already installed and goip4 gateway already installed and configured.
I want to configur freepbx to connect with goip4 gateway 3 lines (simcards)

1.creat 3 SIP user :
user 600 recive call and working with line 1 from number start with 06
user 500 recive call working with line 2 from number start with 05
user 700 recive call working with line 3 from number strat with 07

2.creat variables
if user 600 dont respond he redirected to voicecall to leave a message 1 after that send sms offer 1
if user 500 dont respond he redirected to voicecall to leave a message 2 after that send sms offer 2
if user 700 dont respond he redirected to voicecall to leave a message 3 after that send sms offer 3


ps dont change any network config on goip4 gateway.