Where did you learn playing poker?

I got to know poker through friends, playing in a small group. But I really learned it at the Pokerstar school in 2013. There I understood the basic rules. But really, the biggest learning experience I had was when I was part of a poker team. There I learned strategies and hot spots, as well as many terms I didn't know.

I learned to play poker in a casino, 20 years ago, it was five-card draw poker

Better to see once than hear a hundred times. That's why I prefer videos.

I learn to play poker by watching it on television.

There are several websites available that can instruct you on poker. I made an effort to learn from each of them, including Cardschat, Twitch streaming and YouTube videos. I can tell you one thing, though just like learning to play chess, understanding the rules is one thing, mastering the game is quite another.
If you have never played Texas Hold'em before, searching for its rules on Google would be the best place to start. Download the PokerStars client,
register for a free account and play a few play-money games to gain a feel for the game, in my opinion. Even while free games are very different
from paid ones, you will at least gradually adapt to how things operate at the tables.