First you have to build the library, and install it.
Then you probably get something like
installDir:
|- bin
|- lib
| |- somelibraryname.a
| - include
|- someheader.h
To use this library in your codeblocks project you do the following:
1) Setup the project build options:
1.1) Project->Build options->Select your project name on the left
1.2) Search directories-> Compiler
1.3) Add the include directory for the library
1.4) Search directories->Linker
1.5) Add the lib folder for the library
1.6) Linker settings->Add - the .lib file you can only the name, because you have added the folder to the search directories...
now you should be able to use it in your project.
If you have problems:
http://wiki.codeblocks.org/index.php/FAQ-Compiling_(general)#Q:_How_do_I_report_a_compilation_problem_on_the_forums.3F