I watched the experience bar while recruiting to get a rough idea of how much experience is needed. The bar doesn't have numbers, so it's just an approximate estimate – about half, more, or less. I also checked the hero's profile in the upper right corner, but I couldn't find any information about the amount of experience.

And here's your quote about meditation:
"In my opinion, meditation is useful when playing on a huge map with another player, closer to the end of the game, so to speak, before the final decisive battle. It's also worth remembering that meditation consumes 3 mana units."
How does it consume 3 mana units? Per turn? Or? I read that it actually restores mana. Tell me more about this meditation.