Hello!
I currently have a Gold Experience model made by my modeler, yet he / she has no idea how to port it into Roblox.
I figured it out, yet the textures and colors don’t port with it.
Since you’ve already asked the question I’ll answer. In order to port Textures with the mesh make sure the textures are saved before exporting from blender then export the mesh as an FBX. If the mesh is made up of several parts that is fine. FBX files save all the objects as one file and imports them separately with their texture applied. Typically you’d either have several textures saved or all textures in one image with the UVs organized accordingly.
In the top of the UV Editor, or Image, there would be a button called “Image” to the left of where you create/open UV Textures. Click that, and scroll down to “save image.”