Hey - we'll have a tutorial/combat description eventually. Some key things to watch out for - using a move in yellow is putting you at either low stamina or low stability, using a move that's in red will cause you to trip or collapse. Enemy attacks can also push you over (or in the case of Gutcheck, wind you) so if you use a move that leaves you in low stability and the enemies hits you hard, you'll go down. The easiest build to use right now is a high Strength one - but you can get by with high Magic or high Agility as well if you use the right abilities.
The basic mechanic of the combat system is the Stances - pay attention to what Stance you're in and you'll be able to figure out what moves you can use in each Stance, how to move between Stances and when it's advantageous to do so. Using strong unbalanced attacks in quick succession will throw you off balance and make you trip, so know when to shift gears into a more defensive stance and catch your breath or your footing is crucial.
EDIT: didn't see the other replies before making this one - most of the advice was already given. We're going one stat a time and giving them their stand-out features, so far Strength and Agility are the only ones to have a complete go at that. Agility is very easy to cheese with currently - certain skills will let you trip the enemy, avoid damage while switching stances or even attacking, and crucially disarming the opponent, which will make their attacks do less damage and cause no bleed (although this is less helpful against enemies that can't be disarmed, like the beast girls).