The deck editor is similar to a double set editor. On the left side you have all available cards on the right side the current selected (or new) deck. Here a screenshot:
Deck edit
Documentation in bullits:
cards (one or more) can be selected in each table
the "< <" and the "> >" buttons move the cards from one list to the other
cards are not "stacked" each card is listed as an extra row (on the deck side)
the "heap" of a computerplayer has all available cards and does not remove selected cards, you have an endless supply!
the table can be configured using the context popup, once configured you can save the table state
after editing remember to press the save button
! if you change the name of an existing deck, edit it and save it, you will overwrite the "old" deck, you must use the button "Save as new" if you want a "copy" of your old deck...
between the two lists and between the list and the details each is a split pane bar, which you can drag to get more space for whatever you prefer
on the bottom of the screen you can see stats of your deck for
all colors
each color seperatly
the stats are "Manacost 1-9 and above 10", count of cards, and an average of the mana costs. There is one panel for "All" one for "Creatures", one for "Lands" and one for Sorceries (+Instants). All that for either all cards or each color speratly.