How can I learn to play winning poker without playing with real money? How can I learn to drive a car without sitting behind the wheel? How can I learn to swim without getting wet? etc.
These questions are all based on the false assumption that it's possible to do one of these things without also doing the other. You can play freerolls
or with play money, but you're very unlikely to become a strong, winning player from the experience you gain in those games.
Poker is a game of risk. It's pointless without something at stake.
Now, not all is lost. You can play freerolls until you have enough money to play at a micro table. When you go busto, back to the freerolls and repeat. This cycle will take you a very long time, but it can be done. Or, you can just suck it up and deposit a small amount (say $50) and play the micros with that. You might spend more than that on a nice meal out. You should get a lot of play out of it. Some sites have micros all the way down to 1c/2c. That means you'll have 25 buy-ins.
Of course, you'll want to read and watch videos on basic strategy. Some books and reading will help form a solid game. But, it's something you actually have to do for real to get good at. You can't read a book on how to swim and expect to compete in the Summer Olympics. It's the same with poker.