Rather than manually adding the entire Expansion one card at a time to a binder, you can add or remove it all in one go.
Navigate in Main Menu down to Expansions. Select the expansion you want to add.
Upon selection, you should see Magic Binders section with two entries: Add to Binder and Remove from Binder.
Selecting Add to Binder will let you select a Binder, then it will add the cards which are not already in the selected binder to it.
Selecting Remove from Binder will let you select a Binder, then it will remove all cards of the selected Expansion from the selected Binder.