Rival Theory's RAIN AI is a very full-featured AI to use and it is free. It includes a behavior tree with similar functionality to React, but has more features built in. In fact, this one won't require any additional scripting to go from point A to point B.
To get this going, we'll need the following bases:
To start with, you'll need to start a new Unity project, import Unity's Character Controller, and import the RAIN AI package.
Don't get the RAIN AI package that is found in the Asset store. The current release ...