Alan,
I'll hopefully get a demo up this weekend, but here's a quick description of the way the UI works. I'm not sure how familiar you are with Magic, but I'll assume you've at least read the basic rules, or at any rate can do so if you feel like it.
The Forge UI is basically split into a bunch of small windows. These run more or less as follows.
Your hand. This one is obvious, it's all the cards you currently have available to play. Typically, you can keep up to seven cards.
Your field. This is where creatures, lands, and other cards are played. You can also find status information here, such as the number of cards in your library, life points, etc. Also in the field you'll find a set of phase toggles, which are useful for speeding up gameplay if you don't want to be prompted to play cards in certain phases. By default they are all enabled, which means you will be prompted to play cards in every phase. Fiddling with them is a somewhat advanced topic.
Your opponent's field. This is pretty much identical to yours, except it's where their cards are played. They also have a set of phase toggles you can switch, for when it's their turn.
Card Detail. This is where you find info about whatever card your mouse is hovering over at the moment. Most importantly, mana costs and card text are listed here. There's also information about cards power and toughness or loyalty, depending on the kind of card, as well as some less immediately important data about where the card came from and how common it is.
Game log. This is important, it's the window where everything that happens is shown. It's also the most annoying, because at the moment it's basically a bunch of tiny text fields, and it's easy to get lost in it. You'll want to approach it from the right, as that's the bottom-most log entry. To make this easier to do, open the stack and then move right of that, and then open the log, as it shares the same space.
The stack. This is where spells and effects are resolved. It's another series of text fields, though generally far smaller than the log. Most of the time, it's closed if you don't need to see it.
Combat. This is a window which lists information about creatures attacking you, or which you are using to attack. It shares a space with the stack and the log.
Prompt. This is where you are told information about who's turn it is, who has priority for placing things on the stack, and so forth. It's also where you go to advance through phases when you have nothing to do, just press Ok to pass priority or "end turn," next to it, if you don't want to be prompted for any of the following phases.
There are a couple windows and controls which are less commonly used, such as the dock and the card picture window, but those can generally be ignored by totally blind players.
So the general game flow is like this…
You start a game, which I will demonstrate in the demo, but basically involves selecting a game format and decks for yourself and the AI.
You have a virtual coin toss to decide who will go first.
IF you win, you decide whether you want to play first or draw a card, using the prompt window.
You then get your first look at your hand, and can decide whether to keep it or to take a mulligan, which will let you discard it, draw another hand, and then discard one card from that hand. You might want to do this if you had no land cards, for instance.
When it's your turn, you play cards by selecting them with the NVDA cursor, and then moving the mouse to them with NVDA-shift-M, or nvda-numpad-slash. This is necessary because the card details panel only shows information for the card currently highlighted with the mouse. You can check the details if you're ever unsure about what a card does, it doesn't have to be your card. Just click on the cards you want to play, whether they're on the field or in your hand.
When you're done, you press OK on the prompt window, or end turn. You listen to the sounds indicating what your opponent does, possibly checking the log or stack window to see what they've played. The process repeats with occasional variations, going turn by turn.
Basically, you use the NVDA review cursor to navigate the screens. Each little window is preceded by a title to its left, such as "Zack hand," or "Card detail." To the right of the title is that window's contents, whatever it happens to be.
I hope this helps, and will definitely try to explain more in my demo.