To build a Magic: The Gathering Arena deck, you'll need to collect all the cards necessary for the deck list (click on the images above each deck in our guide to see the cards you need), then navigate to the 'Decks' area in the game client, create a deck, and add all those cards to it
For the event, you can only use cards at either the N or R rarities, often meaning a lot of powerful cards from Archetypes can not be used
Rona, Tolarian Obliterator is a great fallback if you run out of gas and cant loot your way through extra lands
You can also touch/hover on any point on the chart to see details about the price at that particular point in time
Mark Gottlieb (my co-lead for Gatecrash ) suggested that you get to cast the spell first, before it gets grafted, to allow you one use of your spelland often two if you set it up correctly
Obelisk the Tormentor Unleash the true power of Obelisk the Tormentor by Tributing 2 monsters you control and wipe your opponents monsters off the field