As the ug8lib will not bei supported in future the developer suggests to use the newer version
There are reference documents with examples
how to use the library.
To print different strings you might learn how to handle c strings (arrays of character). That's the better choice than String objects for controllers with limited memory.
Just google for c strings Arduino and you'll find lots of tutorials!
If you get stuck feel free to come back with your questions... 
ec2021