Hello Leddy,
White camouflage is hard to paint realistically. Enamel based flat white paint covers better therefore will be a better choice over acrylics.
Prime the figure with flat white then consider how 'used' you will like the figures fatigues. Reference photographs show after a short while the uniforms become very dirty. Grays or browns work best for the shadows, possibly both if a worn a lot look is desired. The trick is to keep the white theme without it becoming a washed out gray or brown. Use enamel flat white for the highlights, Testors has a flat artic white that is a good choice. Less is more with the darker shadow colors.
Look at other modellers work and see what worked or didn't on their winter themes along with the reference photographs.