It's all just fine. But how would we know about what to do where and when?
Right. The maps. As growing, try to notice, what's going on around you at first. Who goes where on the maps, and why. That basic knowledge, will become inveryhandy, on the battlefields. Several guides already exists of several of the maps, but here, I'll share what I know, so far. No matter what map you get, try to change your view on the battle. Look at it as a challenge, instead of matchmaking and Wargaming being against you. You were the one choosing the click on the botton, in the first place. And even the lowest tiered tanks, can still make a difference. No? Ok, then have a look/ watch/view on Jingles' "Epic win" episode 2.
In this gaming world there's a very big Youtub'er and Community Contributor, by the name of The Mighty Jingles. Most days of the week he uploads new videos on Youtube. One video per day, at least.
The video I here mention, is called "Epic Wins2", and contains a replay of a KV-2, tier 6 soviet heavy tank, driving on the map, El Halluf, which we return to later. This KV-2 driver, was in this mentioned battle, in this video, rated to have 16% chance of winning with his team. -And he actually won! If he can do it, so can you!
How?
"By simply, simply trying". Sometimes, it's not enough. But you will never know, until you've tried your best. Screw stats and win-chances. Play with your team, show your enemy what you've got.

The maps will be run through with descriptions of basic tactics, by alphabetically order. This list goes for maps in random-battle rotation.
And as for this site/section goes, as the title says, it's basic. It's to up to you to find spots of concealment, and use of the terrain to your own advantage, to get the enemy taken out.

Abbey

Abbey's the first map in or line.
Now, the map is constructed with three main places, from where the enemy can attack your team. If you together with your team, can be able to cover all three spots of the map, and combine all your guns on the enemy (red) tanks, you stand strong.
Heavies normally goes down/up, the two roads on the sides. Some players find out their favorite tactics. But they should never stick deeper, that you get so in-flexible, that you can't go elsewhere on the map.
In battle after battle, I see players lemmingtrain. And there is nothing wrong with it. As long as it works, and the lemmingtrain focuses on pushing. If it doesn't, the team lemmingtrain'ing, get rushed and outplayed, by the enemy focusing their fire, and working way better together, than the one lemmingtrain.
Mediums and lights mostly go to the Abbey in the middle. Well, mostly light tanks goes to the Abbey in the middle, since it contains great places where to spot enemy tanks for the allies.
Mediums has a more felxble opportunity. Depending on the game, each situation on this map, they can support, actually all three spots. But each medium-tanker has to read the map oneself. On which of the spots, is the biggest need?
Tankdestroyers mostly "camp" back by the base to defend it, as well as the artillery, if such is in the battle. However, sometimes, some tankdestroyers can do better, if they get the chance to go along certain lines. Take one of my favorite clan-mates for example. When ever we get Abbey as a battlefield, no matter if we're toptier or not, spawn on North or South, we like the most to go in line 1-2. But at least some support, is always appreciated.

Artilleries have not much of a choice of where to go. Most arties go to the far back of the map. and shoot at what ever they can.
As an artillerist, myself, I would love if my team could stay alive, keep the targets lit up, and tracked and pinned in place, where I can land shells on them.

Airfield

Airfield is one of the desert-maps.
Here is the hot-spot heavy meeting, going on in the middle of the map. Lots of rocks to hide behind, and sloped grounds into the area, allowing use of gundepression. Depending on the tiers and the amount of heavy-tanks being on the map, the lower tiered or thinner armored heavy tanks has two options. They can either support the higher tier heavies in the middle, or they can support those lights and mediums in the south. Most often it's the southern flanks getting left open on this map.

Lights and mediums mostly go to the southern plateaux, with the ruins of an amphitheatre and some leftovers of a temple. As for spotting positions there can be useful spots in B-C, with luck chances for flanking fire of the enemy tanks fighting in the middle. There CAN be a chance of spotting positions in the middle, but it's quite risky. Reaching to those positions, requires that you can get to the spot fast, but still in time for your allied heavytanks, to keep the enemy heavy tanks occupied.

Tankdestroyers, can go to to the hgiher, minor rocks north to or near their bases. Good sniping positions and chaces of flanking fire.

As for artillery, again furthest behind

Arctic Region

The game of World of Tanks, have got three main types of maps. Summer, winter and dessert. Arctic Region as seen on the picture above, is among the winter-maps. The heavies, at least top tiers meet, on the road as far south as possible, F9-G8. Beware of this flank however! Taking a road too soon, you end drowning your tank. Jingles, a huge figure in this kind of world, who makes videos almost everyday on YouTube, have once said in a video on this map, that heavies of all times, have come to this flank getting destryoed by artillery. So beware of the case, if there is artillery on the battle. Make sure you're in proper arty cover, as close into the rocks, as far below them as you can get. Stay close to your teammates focus your fire on the enemy, but not as close that enemy artillery could get a bombardeer medal, landing a shell in-between you.

Tankdestroyers, like to camp on the roads, "spotting" the middle, and firing at distance on everything passing the valley. So pay attention to the roads just by the mountains near both bases. Don't be surprised, if a shell suddently hits you. There might be a tank-destroyer, sniping from this position.

The roads are in SOME cases also prefered, as scouting positions. But there are other options as well. All the northern flank. Most mediums and lights go here. On this map, it's most opportune, to use the terrain.