Pokemon Go has two sides. There's the fun side of exploring and collecting Pokemon, and then there's a very real business of battles and making yourself Gym Leader.

In the world of Pokemon, battles are central, because that's what Pokemon do. Trainers collect them and they battle in Gyms. That's the same in Pokemon Go and eventually, you'll arrive at a Gym and wonder what you're supposed to be doing there. 

Here's everything you need to know about Pokemon Gyms.

Pokemon Go gyms are where you battle or train your Pokemon. Each Gym is owned by a team and once your Trainer reaches level 5, you'll be asked to choose a team. 

There are three teams: Instinct, Mystic and Valor. They each have a colour: yellow, blue and red, respectively. These colours are useful, because you can glance at a map and see which Gyms are friendly, and which aren't.

Ultimately the reason to be in a Gym is to get the PokeCoins which you can use to buy stuff in the Store to advance in the game.

Pokemon Go teams only exist to manage Gyms. When a team moves into a Gym, it's their Gym and they fight to defend it from other teams by leaving Pokemon defenders there. 

For example, if Instinct own the Gym, other Instinct team members can train there and raise Gym prestige. Mystic and Valor team members will go there to battle against the Instinct Pokemon defending that Gym to try to beat them and lower Gym prestige.

Pokemon Gyms have a level and they have prestige. The level tells you how many slots there are for defenders and those slots increase as prestige increases. A level 5 Gym, for example, will have five defenders and all those Pokemon are from different Trainers.

Prestige is the measure of a Gym and it is this that you can alter by training or battling. You can train in a friendly Gym by challenging a defender. You fight and if you win, the prestige of that Gym increases. Once the prestige is raised enough, the Gym level increases and another defender can be added.

When battling an enemy Gym, it's prestige you knock down with each victory. Once the Gym's prestige reaches zero, the defenders are ejected, and you can move in and claim it for your own team.

The battles, or fights, in Pokemon Go are pretty simple. Whether you're training or battling another team, the mechanics are the same: you tap the screen as fast as you can to unleash your normal attack. Different Pokemon have different attacks, and some Pokemon are more effective than others against particular foes - water Pokemon are effective against Fire Pokemon, for example. 

There's also a power move. This is executed via a longer press, unleashing a more damaging attack on the enemy. However, if you miss, you'll probably have sustained a number of hits for no gain. 

There's also the chance to dodge using a swipe across the display, that aim being to avoid those painful special attacks. In most cases, it comes down to who unleashes the most attacks and who has the highest CP. You are knocked out when your health bar reaches 0.

Training is simple. You find a Gym that's owned by your team and you'll see an icon to train there - it looks like a boxing glove. You can pick one Pokemon to send into a friendly battle. But make sure you stand a chance of defeating the Pokemon you're training against, because if you lose, you get nothing.

You'll fight all the defenders in sequence until your Pokemon is knocked out. At that point, you'll get some XP and the Gym gets a prestige boost. The more victories you get, the better for you and the Gym. Hopefully, it will get enough of a boost to level the Gym up, opening a slot for you to leave your own defender and earn some Coins.

If you're attacking a Gym owned by another team, this is where things get serious. The aim is to beat the defending Pokemon using the battling technique mentioned above. You'll knock the prestige down for each of the enemies you defeat and eventually, once the prestige for that Gym is at 0, the defenders will be ejected and you can move in and claim it. 

However, if it is a high level Gym, with lots of defenders and a high prestige value, you'll struggle to make an impact on your own, and you may run out of time. 

When attacking, however, you can access your backpack to use Potions and Revives to help injured Pokemon and you can swap to other Pokemon in your collection, to continue the fight. By changing Pokemon from one strong Pokemon to another strong Pokemon, you can work your way through several defenders - but time is still a problem. 

Because of the time factor, you'll often have to break down an enemy Gym's prestige bit by bit, or in collaboration with other Trainers to get it down to 0 reasonably fast.

The advantage you have going into a battle is that you take six Pokemon. If you're attacking a level 3 gyms and you have a good roster of Pokemon going into the fight, there's a good chance that you'll win.

Once you're in a Gym, you'll earn a bonus for defending it. That will give you Coins and some Stardust to help buy items or power-up your Pokemon. There's a shield in the top right-hand corner of the store where you can collect your coins and then a range of things to buy, like Lures, Incubators or storage upgrades.

You'll get 10 Coins per Gym that you defend and this is refreshed every 21 hours. You can defend 10 Gyms, and you really need to be in as many as you can for those coins and Stardust to mean anything.

As soon as you get into a Gym this award is given, so immediately head into the store and collect the reward, because there's a good chance if you've just taken over a Gym, that other teams will come and attack it before the prestige is built up again. Sometimes you'll only spend about 10 minutes in a Gym before you're kicked out, especially in busy places, like shopping centres.

Like PokeStops, Gyms are located at some point of local interest. There doesn't seem to be a particular theme, but there are Pokemon Gyms in most of the parks as well as at some churches and clubs in Pocket-lint's local area.