Skillpoints are gained at each levelup.
Levels 2-9 gain you 1 skill point each and you can use it for either +1 attack or +1 defence;
Levels 10-19 gain you 2 skill points each and you can use them for the base skills of your chosen basic class (master or esquire)
Levels 20-... gain you 3 skill points each and you can use them for the skills available for your class.
Skillpoints can be spent on skills.