How to you "catalog" items?

[taiy4ki]

greetings,
So I notice in the trade section people offer cataloging items. I know that means it allows you to buy them from the nook machine on your island and have it delivered the next day but how do you catalog it?

 

[DJStarstryker]

The person drops the item, you pick it up, you drop it, and then they take it back. Because you picked up the item, it adds it to your catalog.

 

[taiy4ki]

The person drops the item, you pick it up, you drop it, and then they take it back. Because you picked up the item, it adds it to your catalog.

Oh okay! Thats simple! Thank you!