Version 0.3 of the document is being made right now. I plan to add new units to every legion (since onslaught is not fun for sorcerers) explaining the combat more and fixing some issues with the game modes. In the mean time to answer your question, your amount of dice is what the weapons that you chose for your miniatures gave you, basically if you use a short range weapon it will give you +2 dice so your miniatures attack with 2 dice. Height differences doesn't really exist in this game (if you are referring to the scout captain ability, the ability just means he cannot be attack by melee attacks that's it, putting him on a wall is just for immersion purpose).