The "Create Event Wizard" will guide you through the setting up of a new event file. The "wizard" is shown when you use the menu item File / New Event File.
This page is shown when you have selected to use two map files. It has two "select file" buttons that you need to use to select the map files to be used.
Condes will store the file names of the map files so that the next time you open this event file in Condes, the program will know where to find the map file. If you move a map file (or open the event file on a different computer), so that Condes cannot find the map file, the next time you open the event file, you will be asked to help Condes locate the file.
The selection on this page affects the map and control settings for Canvas 1, and possibly Canvas 2 (if two printout scales are chosen). You can later change the settings by using this dialog: Canvas / Map - Setup Map dialog