My knowledgeable guess would be: here https://ggbetapk.com/cs-go/. Just click and you'll see the schedule and you can activate the promo code right above it. Just be sure to verify your account beforehand- it's fast. In addition to CS:GO you'll find any eSports there as well. Personally, I prefer DOTA 2.
Dude, the author was saying about counter strike global offensive, not dota. I guess, during the last two years the cs:go became waaaay more popular compared to dota, I guess mostly it is due to the popular players like S1mple. And the author's question, well that is actually pretty easy, you can easily follow and watch all of the best cs:go tournaments, on twitch. You can easily find the streams and watch the games. To be honest, I am actually really addicted to this game right now. I even got almost every single skin form the game. Right now I am trying to sell csgo skins for real money, as I can easily get a lot of money out of these sells.