Hello,
there are some ways to do it.
The easiest is to dearchive the zip-file of the oscat.lib with the S7 manager.
Its the same as you use a normal S7 project.
After that you´ll see the different function folder, for exp. mathematical function.
In these folder you´ll find two further folders ´Source´ and ´Module´.
Now you can copy the FCs or FBs to your application.
Please, have a look inside the SCL source code, here you can see if they are
some external function (FCs or FBs) called. If yes copy these FCs also to your S7
project, otherwise you´ll get a CPU fault.
Greetings
Detlef