I wanted help from someone to design its exteriors (paint, any other material) so that it looks good from outside.

It's not that difficult. Search for images of exteriors like "garden". Reproduce the parts you like in your design. That way even a non-creative person can make great designs.
Call it "Research" [:)] . That's what I do with every single piece of custom furniture I create. Looking up dimensions, the correct naming of parts, etc. You will get ideas along the way.