"Vilja" is the verb in the infinitive, so this roughly means 'to want'.
I want a computer → Jag vill en dator
I will want a computer → Jag ska vilja en dator
In the first sentence, 'vilja' is the action that the subject 'I' is doing. In the second sentence, 'ska' is the action the subject is doing, and 'vilja' is the action the subject will do in the future.
English doesn't really have infinitives like this, so it's a little confusing to try to explain. Did this help?