Ensure that the resulting item class is created.
Data Table -> Don't Change
Row Name -> Result Item [what you craft]
Open the DataTableItem and set only Row Name & Quantity
Repeat and add as many materials as you need.
Inside AC_Inventory_System select Blueprints and add your new blueprint.
You can add blueprints during the game using the AddNewBlueprint function inside AC_Inventory_System.
Tips: After completing a mission you can add new blueprints as an achievement.
Start the game and press 'c' to check if everything is ok.