The game can be found at grid12.com. Go there, log in (or register, if you have an invite code but not an account), and complete the tutorial (if you need to access the tutorial at any time, just type /tutorial into the chat.) You'll probably want to pick a name, too - do that by typing /choosename yournamehere into the chat.
After finishing the tutorial, you'll be taken to the game world. It should look something like this:
Woah! Lots of shiny buttons, numbers, arrows, and symbols! Let's see what they all do. You can also hover your mouse over them for tooltips.
This pane shows performance stats. You can see the FPS, the memory usage, the number of draw operations being performed, and a few others that I have no clue about. None of these are really useful when playing, but if some bug happens, or you run into a lot of lag, take note of the values and see if any of them are unusual when you report the bug/lag issue.
This is your gridshard count. You get gridshards by killing enemies and use them to build stuff - more on that in Part 3.
This indicator is no longer present in the current build. The only reason it's in the screenshot is because I'm too lazy to update it.
This counts how many regions have been completely cleared of enemy fortresses. You can safely ignore it.
Seems like 17 convoys have been killed since the start of the game. Convoys are huge bosses; the goal of the game is to kill 500 of them. When 500 have been killed, the game starts over.
Here's how you access the market. Red lets you see what's for sale, green lets you post a buy offer. More on this in Part 5.
This is your inventory! Loot you pick up can be accessed here.
Here's the chat window. It appears when someone chats, the server makes an announcement, or you hit enter to chat or page up/page down to scroll. It disappears after a few seconds.
The lightning bolts are crystal splinters, which are a type of loot you can pick up; the numbers represent how many of each type you have. You use them to create power crystals, which can refill your health; these are the red diamond things.
Prisms are objects which you pick up that provide a constant passive boost to your stats. This pane shows you the highest level of prism that you currently have, and the number of such prisms. Mouse over it to see all your prisms.
Click here to change what tank you're driving.
Click this button to go to Origin (the town at which you start at). In practice it's used as a instant teleport to safety, but since clicking on a button is too slow, everyone uses the keyboard shortcut ESC or Z instead.
View the current status of your augments here. I'll explain what that means in Part 3.
These are "triggers" - user-enabled abilities. Click on them to activate, or for faster use, press 1, 2, 3, or 4 to activate the corresponding trigger. Each tank has different triggers, so roll your mouse over them after you change tanks to learn what they do.
This is how much money you have. The in-game unit of currency in grid12 is the coin, which is used to buy and sell stuff from the market. You can get coins as drops from convoys, which I'll talk about in Part 4.
Okay, let's move. How? There are two ways to move: mouse and keyboard.
To use the mouse, simply click where you want to go; your tank will turn and go there. If you want to rotate your tank, click inside the green circle, then (still holding the mouse button) drag your mouse outside the circle in the direction you want your tank to rotate. A red arrow should appear, pointing in the direction you want to move. If you're tired of holding down the mouse button, double-click and the pointer will lock, allowing you to move just by moving the mouse.
Moving with the keyboard is pretty simple too! Use up arrow/W to move forward, down arrow/S to move back, left arrow/A to rotate left, and right arrow/D to rotate right.
If you want a track-up orientation rather than north-up ("nausea mode"), hit K.
Moving long distances manually is rather tedious. That's where teleportation comes into play. You can teleport to any other player or any constructed city instantaneously; teleportation has no cooldown as well.
Zoom out (hit E, or scroll down with the mouse). You should see something like this:
Players are indicated by green tank icons - in this picture, HKTnoSiO is north of me. Constructed towns (those you can teleport to - more on this in section 4) are given by the blue circles with the pink or blue borders. To teleport to a player or a city, just click on their icon. Once you get to your destination, you can zoom in again by pressing Q or by scrolling up.
If you know the name of a player or city, you can type /goto cityname or /teleport playername into the chat. These commands substring-match, so you could, for instance, type /goto ori to go to Origin, provided that there are no other towns with "ori" as part of their names.
Before we end the section let's look at all the keyboard controls.
We've already seen the use of WASD and the arrow keys to control your tank, K to change the camera view and control scheme, and Q and E to zoom.
F toggles the pane fade animation. It looks nice, but if you're on an old machine, turning it off may improve FPS.
M toggles music, and N toggles shooting sounds.
J toggles HP bars. I highly recommend you turn this on, since it allows you to see how much HP your allies and enemies have at all times.
B toggles a starry overlay. It doesn't do anything but make your screen look dirty while giving you lag. If you see some strange white spots on the screen, hit B to make them go away.
If at any time you need to view the list of commands, type /help into the chat.