project protel99se
Hi
Click on the schematic component name in the library list that you want to add the footprint to, click on edit and when the editor opens, click on description, type in the footprint reference from the footprint library in the box and save the modified library. Close your project and reopen it and your modified schematic symbol will be there, you must do this to force protel to read the library file again.
If you do not want to edit your libraries you can just double click on the schematic component symbol and type in the name directly for just that one instance of the component.
The only book on Protel that I know is the one that was supplied with the package. That is quite a good manual if you can find one now.
Bob.