how to win?

2 times lol
the above-mentioned point was not given away for free, lol)

That's when you learn how other people play, you won't be writing on the Internet:

Water is often not used at all. Although very rarely, thanks to the "Clone" spell, you can perform miracles.

I can't find right now where and who wrote this, just to give a link, but I'll retell it in my own words (and I can confirm): in "Heroes," there are quite a few self-confident offline players who considered themselves "cool" until they went online and learned about the level of play of other players. And when they find out that, for example, a map that they completed in 300 days is completed by experienced players in 60 days, they start to freak out: "how is that possible?!" :)
My level of play started to grow precisely after I started reading what smart people write on forums. Otherwise, I would have remained a clueless noob. And in 2020, it's worth using the possibilities of the Internet to the fullest.
And you should start with this invaluable document, which contains the experience of thousands of players: FizMiG. This is practically the bible for every Heroes player. Official page: https://vk.com/fizmig