Found Problem. [SOLVED]
hope I can explain this properly.
After I installed book library basic. The pre-installed categories were showing, any new category that I added or any books I added and published under the new category would not display.
Finally I went into my phpAdmin and figured out the problem.
Under the database table booklibrary_main_categories , there is a column called params. Each pre-installed category had "-2" as its input.
The new categories I created by not have any text, I manually added "-2" under the "params" column.
Now all/new categories and books under them show on the front end.
Just thought I would post the solutions so if anyone else with a similar problem, may find this solution helpful.
Thanks