Hello Im New in openwrt and i wanna know how its possible to build the openwrt rom using the Cudy GPL Code for the m1300 v2 ?
You'll need to ask Cudy since they are the ones providing that code.
If you want to use official OpenWrt (obtained from openwrt.org), we can help you here. There is extensive documentation about building from source from the official OpenWrt codebase, but this may or may not work with code provided by other vendors.