" Following to Join Basis"

[babu]

Hello
I filed my I485 got a notice for FP recently and I will be getting married in September. I like to bring my wife on "Following to Join basis" Could someone help me where I can find filing procedure. Also, please let me know if I my wife is eligible for Following to Join basis, if I get my I485 approved after my marriage and before filing her

Please help me I can't fine relevent information anywhere.

Thanks