You can join it here.
Articles about strategy that will help you out here.
The website also has an app if you need to put in last-minute orders. It's primarily a social game; only one person can win but nobody wins alone.
The Map, Units, & Object of the Game
1. Seven players represent the major powers of pre-WWI Europe: Austria (red), England (orange), France (dark blue), Germany (beige), Italy (green), Russia (purple), and Turkey (light blue).
2. The map is divided into named “provinces”. There are three types of provinces: inland, coastal and water.
3. There are two types of units, “armies” and “fleets”. Armies can move (or retreat) to inland and coastal provinces, fleets to coastal and water provinces.
4. Only one unit can be in a province at a time.
5. All units have the same strength, a force of 1.
6. Units combine their force with “support” orders. In conflicts, the unit with the most combined force wins.
7. There are 34 “supply centers” (provinces marked with stars). Powers start with 3 or 4 supply centers, their “home centers”.
8. To win, a power must control 18 supply centers. If all the players still in the game agree, a game can end with survivors sharing equally in a draw.
Sequence of Play
9. Each “game-year” proceeds through five phases: Spring Orders & Retreats and Fall Orders, Retreats, & Builds. Retreats and builds phases are skipped if no player has orders to be made. The game starts with Spring 1901 Orders and ends when there is a winner or a draw is declared.
10. Players communicate 1-on-1 or in groups using the messaging systems during any phase of the game.
11. Orders are entered secretly for each phase and revealed and resolved for all of the powers simultaneously at the end of the phase.
Orders Phase
12. You may give orders to all of your units. Units may be ordered to do one of the following:
Hold in place.
Move to an adjacent province. Armies in a coastal province may move to a non-adjacent coastal province if convoyed. Fleets in a coastal province may only move to provinces adjacent to the coastline.
Support. A unit holds, adding its force to another unit. A unit can only support an action in an adjacent province to which it could have moved.
Convoy. A fleet in a water province holds, convoying an army. (A fleet in a coastal province cannot convoy.) Convoys can be by one or a chain of fleets. The first fleet must be adjacent the moving army, each fleet in the chain must be adjacent the prior, and the last fleet must be adjacent the destination.
13. You may support and convoy another power’s units.
14. A unit ordered to move cannot be supported to hold. A unit ordered to hold, support, or convoy may be supported to hold.
Order Resolution
15. If units of equal force move to the same province, they “bounce” and neither advances. If one of the units has greater force, it advances.
16. Units ordered to each other's province with equal force bounce and do not switch places (unless one is being convoyed.) Three (or more) units can rotate positions.
17. A unit with a move order that is bounced retains a force of 1 to defend against an attack in the province where it started the phase.
18. A unit can only be forced out of its province (“dislodged”) with greater force than the unit plus all of its support to hold. For example, a unit moving with two supports versus a unit holding with one support, a force of 3 vs. 2, dislodges the holding unit.
19. Support is “cut” if the supporting unit is attacked from any province except the one where support is being given. Cut support is not added to the force of another unit.
20. Dislodged units have no effect on the province where the unit dislodged it came from. Support orders from dislodged units are always cut.
21. A dislodged unit can still cut support or cause a bounce in a different province from the one where the unit that dislodged it came from.
22. You cannot dislodge or cut support of your own units.
23. If there is a unit in a province where a bounce occurred, it is not dislodged.
24. If a fleet with a convoy order is dislodged, the convoy is “disrupted” and the army being convoyed does not move. Attacking without dislodging a fleet in a convoy has no effect.
Retreats
25. A dislodged unit must either retreat to a vacant province where it could have moved or be destroyed. Armies may not retreat via a convoy.
26. Units may not retreat to a province where there was a bounce or from where the attack came.
27. If there is no legal retreat for a dislodged unit, it is automatically destroyed. If two units try to retreat to the same province, they are both destroyed.
Builds
28. You gain control of supply centers by occupying them after the Fall retreat phase. They are yours until another power gains control of them.
29. For every supply center you control, you may have one unit on the board. During the Fall Builds phase, if you are short units, you may build new ones in unoccupied home centers, while if you have too many units, you must disband the excess.