I don't do dioramas -- it's the lack of the creative and artistic genes. But having seen other reviews of these MiniArt diorama kits, I had to see one for myself.
The very first thing I did is go to the MiniArt website and go through both the Assembly Guide and the Painting Guide. The Assembly Guide is excellent even if you are familiar with vac-form kits as there are some differences from, say, an aircraft vac-form, mostly due to the corners and molding practices. And the Painting Guide pretty much shows even the least artistic of us how to get good effects with paints, primarily oils. You can do the quick tour by just reading the captions and looking at the still pictures, or you can also watch videos accompanying most all steps.