So this is a very basic run through on how the currency and tech tree work. It is actually very simple, and will leave a few of the more complicated things till the end so if you see something that confuses you, just ignore it and if I haven't gone over it by the end just ask. So here we go.
There are 7 nations which you can play as and each has a technology tree that looks like this. You start off with a tank from each nation, the very first tank in the tree (the one on the far left). To get new tanks you must research them and then buy them. To do this you need currency.
Currency
There are 3 types of "currency" in the game: credits, experience, and gold.
Experience and credits are both earned just by playing. Click the big red BATTLE button in the top of your screen and once you have finished the game you will be rewarded with some credits and research points. The better you do in the game, the more you get and you will get substantially more for winning than for losing.
Experience is used to unlock upgrades and new tanks. You need to unlock each upgrade and tank before you can buy it with credits. The experience you earn is locked to the tank you earned it on and you can only use it on that tanks own research tree. Credits are used to buy just about everything. You need them to buy ammunition, repair your tank after each battle, buy upgrades for your tanks and to buy new tanks.
Gold is bought with real life money and is not required to play the game. It can be used for a lot of things, like buying premium tanks a few other things that generally allow you to make a bunch of quality of life shortcuts through the game. Don't worry about it at all until you are familiar with the basic game mechanics.
The Tech Tree.
Each nation has a [tech tree]( that shows all the tanks that that nation offers, and each tank has it's very own research tree, that shows the upgrades that are available for that tank. The tanks are arranged by tier, from 1 to 10 (or I to X, roman numerals are used extensively in World of Tanks). Tier one tanks are earlier, pre WWII tanks and tier ten tanks are much more advanced tanks from end/post WWII. To get to the more advanced tanks you must earn experience on the early ones.
I have this tank. This is it on the German tech tree. As you can see, I have earned 10,854 experience on this tank. If I click the tank on the tech tree or if I click the RESEARCH button I will get to that tank's own research tree. This is where I spend experience to research upgrades and eventually the next tank along in the tree. The icons that have a big yellow tick in them are the upgrades I have installed on the tank currently. The icons that have a number and a silver star in the green bar are upgrades I have yet to research. The icons with a number and a small stack of coins in a yellow bar are items I have researched but not bought.
For example, I have not researched the upgraded tracks and they would cost 1095 experience were I to do so. You can also see that I have researched, but do not own, the "5cm Kw.K 39 L/60" and if I wanted to buy it, it would cost 13,970 credits.
New tanks: You can also see that there are 3 tanks in the [research tree]
