How do the Seventh Day Adventist approach Old Testament laws?

I know the Seventh Day Adventist church is known for following certain Old Testament laws found in Leviticus such as the food/dietary laws. However I'm also under the impression that they don't follow all 600+ Levitical laws either. Is there a reason why they follow certain Levitical laws like food/dietary but don't follow others, such as wearing clothing made of two different materials (Lev 19:19) or cutting the hair at the sides (Lev 19:17)? To what extent do they keep the laws?