After you have set the source file type and the source file directory as well as the schema type Secondary Contacts some options will appear in the navigation bar:
3. Conditions
4. Parent Record Identification
7. Misc Options
8. Translation
To get to the setting Easy Mappings you either click on the right arrow in the lower bar or on Easy Mappings in the navigation bar.

You can always switch between the options by clicking on the arrow buttons or by clicking on the particular option in the navigation bar.
The settings Easy Mappings, Virtual Columns, Conditions, Conditional Mapping, Merge Options, Misc Options and Translation are similar to the ones for the contact import.
The setting Parent Record Identification is already explained for the company import.
All explanations can be applied on the typical fields of the Secondary Contacts.