This support article outlines the steps to printing an initial pick list prior to creating your order Fulfillment records.
Step 1:
Launch the barcode scanning app
Step 2:
Choose the Pick option from the menu
Step 3:
Scan your Sales Order or type in the Order ID
Step 4:
Using the Print Pick List button on the right, select that button. Lead Commerce will then send you a single Pick List for the warehouse you have selected.