How to connect Xbee gateway to xbee ProS3B without xbib dev board?

I want to know how to connect a xbee gateway to a network of xbeePro (900hp), I tried using the same PAN Id on all the modules but the gateway does not find them.

which version of the gateway do you have? What is its full part number?

Also what is the firmware version you are working with on the XBee PRO S3B modules?