The support literally does what it says on the tin. It supports the rest of the team to help the core players win the match. A super-strong support will probably not win a game on their own.
But if they enable the rest of the team they have done their job, even if they do die a lot and end the game with nothing more than brown boots.
Learning how best to help your team as a support is a complicated task, sometimes throwing your life away can even be for the greater good, but before you can understand those higher-level strategies you will need to learn the basics.
Where do I play?
Wherever you are needed is the simple answer to that question. Generally speaking, every team will have two supports, a position four and a position five.
The four will usually take a little more farm than the five, but both fill a very similar role. At least one is usually positioned in the safe lane with the carry, which is the bottom lane for Radiant and the top lane for Dire, to make sure that they are safe and can farm well.
The other support may also choose to be in the safelane, but could also be in the offlane or roam around the map and try to team up with other members of the team to secure early kills. All of these strategies are perfectly valid and it really depends on what heroes you pick and what the enemy is doing.
What is my goal?
As a support, your primary goal is to enable your cores to do the damage needed to kill the opponents and try to keep them alive. In the early game, this is done by keeping them safe in lane, trying to harass the opponents out of the lane and generally making sure they can farm well.
As the game progresses you will want to try and set up kills for your cores so they can get even more money and as team fights break out you will want to both focus on disabling and damaging opponents but also saving your key players if you can.
Supports also have the unenviable task of providing vision to the team by buying and placing wards and are also expected to sacrifice themself if it means one of your cores will live.
What heroes are good for a support?
There are many good support heroes in Dota 2, and while quite a few have quite difficult skill sets to learn, there are some simpler ones that will always be effective.
Crystal Maiden has multiple ways to lockdown opponents and can also benefit her team with high damage potential and global mana regeneration.
Witch Doctor can also offer big damage output as well as being able to heal teammates, while Skywrath Mage can silence and slow opponents. Other options for beginners include Shadow Shaman, Lion and Dazzle.
Tips and Tricks to improve your game
Help your carry farm
In the laning stage, your job is to get your carry as much farm as possible. The big part of this is making sure they do not die, but sometimes you can even put more money into their pockets.
If the lane has pushed into the opponent’s side of the map then you can pull creeps from the small jungle camp into the lane to pull the creep equilibrium back to your side and allow your carry to farm in a safer location.
You can also stack jungle camps every minute to put more creeps in there so there is more money available when your carry goes and kills them. Always be thinking about how you can get your carry more money.
Buy and place wards constantly
Not placing wards is one of the biggest mistakes a support can make, as they give you some of the most valuable information you could need.
Having good vision of your opponents allows you to plan fights and not get caught off guard, so you always need to have wards on the map. If you are a support buy wards whenever you can, they will almost always be more useful than any other item you can purchase.