The first thing you should do is set up a global variable or a stat for the HP and XP. This can be done in the Skills Preferences Window:
For more information see Settings.
Now you are prepared for the scene. Either make a new or an existing one, where you feel comfortable. In order to make a gameobject be able to use skills, it needs the Skills Component attached to it.
On the Skills component you can choose to use a Skill Bar or not. If you decide to use one, you need to drag and drop the Skill Bar prefab into the scene and assign this gameobject to the variable on the gameobject with the Skills component. The prefab can be found under
If you want to use a Skill Bar you also need to add the SkillBarSillTreeAssignments prefab to the SkillTreeUIManual or SkillTreeUIAutomatical prefabs (done by default). If you decide not to use this feature, you should delete it from the SkillTreeUI prefabs. These can be found under
Refer to the Skills Examples for a setup.