To open File Association Wizard select Tools > File Association Wizard menu command. Then, follow the wizard steps to import your project.

 

Step 1: enter the file's extension you want to associate to a program.

 

Step 2: enter the description of the file association, select the program that will be associated with the file's extension and then enter the index of the icon that you want to use for the files with this extension (it is the index of the icon stored in the program's file you have select).