Just mess around with the menu functions and buttons and stuff, you'll figure it out. You can't do everything, unfortunately.
I usually use it for pre deck-building, as well as solo-playtesting. (When starting a new game, choose solitaire game and you can solo-playtest and fool around with stuff to figure it out better).
One of the buttons on top of the screen opens the deckbuilder. You can set your filters and then hit the GO button to narrow your search.
The game does not enforce the rules, it just lets you move cards around. Just like in real life. You can recreate most game effects, but it doesn't let you go into sideboard in the middle of the game for wishes, and it doesn't like really large decks, so Battle of Wits is out. Also, you can turn cards face down for morph and such, but you have to drop them face-up first, so the surprise aspect of Morph is ruined. Try right clicking on cards once they are on the playing surface for more options.
The good thing is you can build your fantasy T1 deck for zero dollars, and play against somebody with it for fun.