See the sample data file below.
Note: The final column in this file is not intended to be mapped in the import.  This is provided as a description of how the Pledge schedule will be in the final results.

See How to import pledges and recurring gifts with installment schedules (includes sample data file) for more detailed instructions on importing Pledges and Installment schedule.

Importing Pledges with an Irregular Schedule requires 3 separate imports.

Import 1 will import the Pledge with nothing populated in the Frequency fields of the import.  This will default it to Single Installment.  Automatically Add Installments option should NOT be selected.The Gift Import ID must be assigned so it can be used in the subsequent imports.

Import 2 will import the Installments.  Each line in the import File will be a separate Installment.  The Gift Link will be the Gift Import ID from Import 1.

Gift Link>GFLink (This is the Import ID of the original Pledge)
Installment Import ID> GFInsImpID (leave this blank, the system will populate it)

Import 3 will be an import to update the existing Pledge to change the Single Installment on the schedule to Irregular.