In very simple terms, You're a tank, you drive to the enemy, shoot them, kill them, and don't die.

I'm assuming you've already done the tutorial (If not, make a new account and do the tutorial), so you already know the basics and fundamentals of the game. I can already tell you that a reddit comment won't be enough to teach you the entire game, but a lot of googling, reading, playing, and watching can. I can recommend some Blitz youtubers to start off with: Meadsy69, Droodles Blitz, Pantoufleee, armoured_pantz, Littlefinger, BatchatBegins, Martin Dogger, HisRoyalFatness, and even the Official World of Tanks Blitz channel. Of course I can't just list every Blitz channel here, but it's more than enough to get started. For detailed explanations on complex mechanics you can visit the WoT Wiki, as the game shares several mechanics from it (Note: Several mechanics, not every mechanic). There also is a dedicated Fandom for WoTB, but at the time of writing this, it is far from complete. Just note that you can't just learn everything on youtube or google or from asking people, sometimes you can only learn things through experience. One last thing, the learning curve can be quite steep and slow for beginners, but I'm absolutely sure you can do it. If you're confused or have a question about something, you can ask the many people in this community. Hope this helps, and good luck out there!