At this step the files of your web application need to be packed into TAR archives and added to the /apps folder. Plesk 'recognizes' two TAR archives: httpdocs-files.tar and cgi-bin-files.tar. In other words, it is expected that the developer will isolate all application files in two groups (TAR archive files) according to the following principle:
cgi-bin-files.tar archive. When installing the application on the domain, Plesk will copy these files to the application folder created in the cgi-bin host directory. httpdocs-files.tar archive file. When installing the application on the domain, Plesk will copy these files to the folder specially created for this application in the /httpdocs host directory or in the /httpsdocs one if it is planned to run the application using the SSL-protected connection. Each group of files can be organized into a convenient folder structure within the TAR archive if necessary. In this case this folder structure will be also copied to a proper folder during the install procedure.
Note: The above instructions refer to the most common situation when the application presents a complete executable unit composed of a definite set of files. But sometimes the application files do not exist at the stage of forming an installation package yet, e.g. they would be generated by installation scripts during the install routine. In this case, leave the /apps folder empty - Plesk considers such installation packages valid anyway.
Thus, this step should result in one or two TAR archive files, httpdocs-files.tar and cgi-bin-files.tar, created and added to the /apps folder, or this folder can be left empty, provided that a special installation script file added to the /scripts folder would generate the application files during the installation routine.