full rules

my abridged version:
The goal in this game is control 18 supply centers (those black dots with a little border around them). The game can also end if every remaining player votes for a draw and that is often how games end. To take over anything, you will need to know how to manage your armies and your fleets. There may only be one unit per tile. You control them with orders. There are 2 movement phases per year, spring and fall. You will send your orders to me (i'm still debating how this should be done). You may not tell other players your orders, but you are allowed to coordinate with them, form temporary alliances with them and backstab them, the game is called Diplomacy after all. Types of orders described below.

HOLD/DEFEND ORDER: The unit doesn't move anywhere, pretty self explanatory. This is the default order and doesn't need to be mentioned in. Examples: Army in Ruhr holds. Fleet in English Channel holds.

MOVE/ATTACK ORDER: Also pretty self explanatory, but whether an attack succeeds is explained in the interactions section further below. Example: Army in Ruhr attacks Holland.

SUPPORT ORDER: This supports either an offense or a defense, for more info on them, view the interactions section. Remember to always state whether you are supporting an attack or a defense. Different countries can help each other attack or defend. If a supporting unit is attacked, that unit's support order is canceled. This is called cutting support. Examples: Army in Burgundy supports attack on Belgium. Army in Burgundy helps defend Picardy. Fleet in Mid Atlantic supports fleet in the English Channel

CONVOY ORDER: This is a fleet only order and only armies may be convoyed. If any of the fleets isn't overpowered, the army that is being convoyed successfully travels through. Example: Army London to Picardy, Fleet English Channel convoys army London to Picardy.

Now that we have went over the orders, let's go over some of the basic interactions.
1. Equal forces - if there is an equal amount of armies attacking and defending a space, they sort of bounce back. Example: Let's say we have the order Army Picardy attacks Belgium from France and Army Ruhr attack Belgium from Germany. The forces are equal, and the units will return to their starting spaces.

2. Greater forces - If any unit is overpowered by enemy forces, they are forced to retreat. This is addressed in the retreat phase, where you can pick where your defeated unit retreats. You may not retreat to where another unit has just lost a battle or where another unit is planning on retreating. If you can not retreat anywhere, your unit is disbanded and removed from play

That's pretty much most interactions resolved. Now for some rules about supply centers. You are considered to control a supply center if you currently have a unit in it or the your unit was the last one to step in it since last year. Each supply center can support one military unit, so Powers that have gained supply centers over the course of the year can build new units. New units may be created at any of the player's unoccupied home supply centers, but only at these centers, and at most one unit per center. For this reason, no more than 3 new units per player can ever be created at a time (except in the case of Russia, which has 4 home supply centers). Supply centers only change ownership if they're occupied at the end of Fall; they do not change ownership if a unit moves through them during the Spring, but leaves again in Fall. If you have more units than supply centers at the end of the year, then you must disband units to even out the number of centers and units.

Austria - Army in Vienna, Army in Budapest, Fleet parked in Trieste
England - Fleet parked in London, Fleet parked in Edinburgh, Army in Liverpool
France - Army in Paris, Army in Marseilles, Fleet parked in Brest
Germany - Army in Berlin, Army in Munich, Fleet parked in Kiel
Italy - Army in Rome, Army in Rome, Fleet parked in Naples
Russia - Army in Moscow, Army in Warsaw, Fleet parked in St. Petersburg, Fleet parked in Sevastopol