Getting started with any wargame can be difficult, esspecialy
when it comes to painting your first model, I am no expert but I
would tell you to just have fun with it, and try to pick a model
you dont really want on your field. It probably won't turn out how
you expect.
Case in point, my first CSM model for 40K was a disaster,
thick paint, chunky finish and an awful flesh tone.
But it gave me my first taste of how painting this type of model goes,
being based on Firstborn Marines they have large panels that makes
putting a base coat on a breeze. However, being a chaos model they are anything but simple.
One thing I would reccomend is painting in subassembalies.
take each part separately and go slowly. My big mistake was painting it as a whole on my first attempt.