If you purchase on-line, it should ask you to link them to profiles from your Family & Friends list in
MDE.
If you purchase by phone, you would be able to link either the will call confirmation or exchange certificate ID numbers (depending on delivery method).
Once linked to MDE, you can make FP+ selections up to 30 days prior to day of yse. If you also have a resort reservation linked to MDE, you will be able to make FP+ selections beginning at 60 days from check-in.
You will still need to stop at either a Guest Relations or Park Ticket Window to exchange for the actual passes. The expiration of the passes will be one year from when the CM hands you the actual pass.