motionworks
Remove that combine at the end.
Right click the "snowfall" node, and select "Pin as underlay". Now any colormap or gradient map you create will show your diffuse color overlayed on your terrain.
To export color, or any data from any node, right click the node, and mark for export. Then all available data will show in your build manager.
I suggest you skim through the docs first though, get the fundamentals straight if you have a problem understanding standard workflows. Here's the link to the official documentation: https://docs.quadspinner.com/