Question on where to pick up airport travelpass with 1 airport express ride in Hong Kong airport

if i purchase online the airport travelpass with 1 airport express ride (i plan to use it on departure day) with 3days unlimited MTR free use, where can i claim the airport express travel pass card? can i get it at the airport station or do i still need to go to kowloon or tsing yi or central station to claim it?