Guild Wars 2

Thanks for your help! Sort of unrelated, but have instances changed much from how they were at launch?

At around launch I started playing and got my warrior to level 46. I just logged on to play for the first time since then and have forgotten almost everything and am lost.

What is the basic gameplay and mechanics of the warrior? Is there clearly a a best build for leveling?

I learned that the skill points have been changed and I currently have 3. I looked for guides on builds but they seem to refer to the old system. I was looking at the defense ability to regenerate health but it’s locked. What has to be done to unlock the skills?