To be honest there is a lack of complete information anywhere. But after much search, and testing I managed to done it.
In the first place the here+ need to be set with a fixed position. And also the data that export out needs to be RTCM3. Usually it comes with UBX+NMEA +RTCM3.
And buadrate needs to be 460800
hopes this helps anyone who wants to set up your own RTK base.