Unzip the library
Copy the .jar and .xml to the folder b4android/LibrariesAdd. Don't put it in the folder Library!
Don't forget to set the path using Tools->Configure Paths->Additional Libraries
Check at the Libs tab, Refresh if necessary.
Copy the class to the project folder where your xxx.b4a located
Open your project.
Project->Add Existing Module->point to the class you have added.
I hope it helps