For extra slot you send a note to the group with the horse you want it applied to, and then add it to the reference
after it's been confirmed.
Twin potions are used when you send in a breeding request.
Regular import is just to send a note with the color you'd like so you can get the correct geno and an ID for the
design you'll either make yourself, ask someone else to design or take to the design corner of the group.
Hope this was helpful for you