The order in which AutoLISP and application VLX files are loaded is important to ensure that the functions used by a file are made available when they are needed.
When building an application with the Application Make wizard, you can control the order in which files are loaded into AutoCAD. File load priority is set in a top down order, the first file listed is loaded and then the next, and so on until all files are loaded for the project. The program files that define utility or common functions should be loaded first and thereby should be listed near the top of the file list. Your main program should be loaded last.
For example, the Garden Path tutorial utilizes a number of different AutoLISP source files to define utility functions, object reactors, and the main program. Many of the utility functions are stored in the file named utils.lsp, this file should be listed at the top while gpmain.lsp should be listed last since it is the main file of the program. The gpmain.lsp file also contains the following code to give the user some information on which command they need to use to start the program.
(princ "\nType GPATH to draw a garden path.") (princ)