The Field Selection screen shows you the SAP fields that are used to filter work orders from SAP. These fields come from the SAP work order header and are those fields which are used in SAP’s work order selection screen (see SAP transaction IW39). Some fields like Begin Date and End Date are mandatory and are shown as already ticked and greyed out.
Go through the list and select the SAP fields that you want to see in your filter. Remember that later on in the wizard, you can arrange these fields in any order and in multiple tabs.