In the beginning of the game you will start with a basic attack and heavy attack that uses quite a bit more stamina than basic attacks by using these in the beginning of the game you will unlock your first sword skill. This skill will differ weapon to weapon and the amount of stamina it consumes will differ weapon to weapon.
So how do you learn more sword skills? The way you would learn anything. Doing it, over and over again :P
You will find these skills leveling by themselves without you having to grind just by completing quests and adventuring. Changing your weapon from a two handed axe to a one handed axe or the other way around will mean you will have to start the exact same way but when switching back from the one handed to two handed you will keep your skills.
You will be able to travel the world finding teachers for different weapons that will be able to teach unique skills. So all in all this works the same way things work in life. You do it over and over again until its perfect!
Hope you guys enjoyed! More news shall be coming out when we are ready to share. :)