Ah Dystopian War... maybe one day I'll manage to get my hands on one of these minis. I was very interested by that game some months ago but it's so difficult to get the actual models that I'm beginning to think that that game doesn't exist and is just the fruit of my imagination.
I wish you good luck with your first painted miniatures. Don't hesitate to use small metal models instead of plastic ones for your first try as you can easily clean them so they are very good when you're not 100% sure how the final paint will look like and you're testing different combination of colors.
After that on the other hand, you'll see that plastic miniatures are quite nicer to paint and manipulate, while metal ones, especially the big ones, will hate you, and you will hate them too