This article will explain the basic mechanics of the game.
Your Squad is your deck. Each Squad consists of a Warlord and 8 Cards that you can switch in an out of your Inventory. Only one Squad can fight at a time, but you can save up to 4 Squads, one under each of 4 unlockable Warlords. You can use the same Card for multiple Warlords.
It should look something like this:
Your collection of cards is the total amount of heroes you have. You can see your entire collection below your squad.
When you enter "Fight" you will see this screen:
Although it probably will look a bit different.
You can see your rating points, and how many more you need to get to another League at the top
You start at League 30, and for obtaining higher Leagues for the first time, you unlock heroes you can obtain from chests and summons. At League 24, you start to lose rating points from loses. You can also click on your current League, so you can see what heroes you unlock for obtaining that League.
By default, you get 4 chest slots, and there are offers to unlock another chest slots. On the far left, you can open a chest with common/rare cards after you get 3 wins, you can open this chest 3 times and then it goes on 8 hours cooldown.
When you click "Fight" you will get a PvP-fight encounter, where you get to fight against an AI-controlled Warlord that is another player's Squad..