Source is the source of the data (Eg. a bundle code such as ca_objects.external_link Most of these codes will be specific to your installation.
Options is a JSON-formatted block of options that modify what is exported.
To get the internal object_id use the source code ca_objects.object_id
Codes are generated as <table>.<code>. Eg. if the element code is "external_link" then the full code for that element on an object record is ca_objects.external_link
The easiest way to get the codes is to do to your user preferences, select "Developer" from the side menu and enable the option to "show bundle codes". Then edit a record of the type you can to export and you'll see next to the field titles is the code. If you click on the code it'll transfer it to the clipboard for easy pasting into the exporter mapping worksheet.
