Blender Mesh Exported to Roblox Studio without any color

Hello!

I am sorta new to Blender still learning things on the way and I created a basic Milk Carton but when I added Color and Export it into Roblox Studio It came out without the color I added In Blender. I tried many times and checked Tutorials on Youtube and It still came out the same. I am not sure If I am missing something else or Exporting it into the wrong file.

-Blue

i think is this?

I followed every step but It’s still the same thing. I am not sure If I missed something I didn’t see. I double checked everything.