Instructions
Press the "AR DS Code Output" button. There is a column of buttons in the upper left-hand corner of the Pokesav program. The one you're looking for is the bottommost button. This will save your information as a text file on your desktop.
Open the Code Manager. The Code Manager is the proprietary software that comes with the Action Replay DSi, and as the name implies, manages the codes it uses.
Drag and drop the text file from your desktop into the left-hand column of your Code Manager screen. This will add the data you generated in Pokesav to your Action Replay DSi. From here you can organize and use it in game.