First, ensure that the library files are in the right place:
If you have a Network install, this will be on your ConQuest network drive, most likely a location such as Q:\ConQuest Q Series\Libraries, but on a standalone install it will be C:\ConQuest Q Series\Libraries.
Make sure that there is a folder for the library in the Libraries folder and that it contains the library files - a zip file will not work, you will have to extract it and put the folder and files in place.
If you are renaming the library you must ensure that all the files are renamed to have the four-digit code you require. For example, if you are working with a copy of RDBR and wish to work with it under the name RDB2 you will have to rename every file in the RDB2 folder to replace RBDR with RDB2
Note: be careful not to remove or alter anything else in the filename.
Once you have the files placed, configure your ConQuest:
Go to Options then select Libraries on the left.
If the four-digit code does not exist, on the first empty line, enter it in the box on the left
Click the Change button to the right of the line.
Select the folder where this library's files are then click OK
Click OK on the Options window, ConQuest will restart
The library should now be available to select when you're creating a project.