how do I associate mesh group to support region in fluid domain?

Our project is a simulation of dam flooding on terrain, we are using VOF operation ,but I am facing an error related to mesh group and support region of vof . how do I associate the mesh group  to support the region in fluid domain?

Edu ​​​​​​​3DEXPERIENCE ​​​​​​​SIMULIA Simulation​​​​​​​​​​​​​​