If you have moved a source file, or if for some other reason Prism can't find it, you can explicitly add its directory to Prism's search path.
From the menu bar - Choose the Use selection from the File menu. This displays a dialog box, as shown in Figure 3-5. To add a directory, type its path name in the Directory box, then click on Add. To remove a directory, click on it in the directory list, then click on Remove.
From the command window - Issue the use command on the command line. Specify a directory as an argument; the directory is added to the front of the search path. Issue use with no arguments to display the list of directories to be searched.
No matter what the contents of your directory list are, Prism searches for the source file first in the directory in which the program was compiled.