What exactly are the facts?
well, of course I can't possibly list them all. From nested higherarchies to geographical distribution, fossils (includes transitional fossils), homologous structures, analogous structures, and vestigial structures, to the fact natural selection has been observed, and that even SPECIATION (macroevolution... a population of one species turning into another) has been observed.
How long ago we became humans with intelligence to use fire and tools to hunt?
I must say I'm not very familiar with human evolution, but I do know some things. the process of getting intelligence to uste fire and tools to hunt happened in gradual steps. There's no single time when hominids started using both tools, tools to hunt, fire, etc. First it started out with simple tools, like using a stone to shatter bone so the bone marrow could be eaten. Then it went to sharpening those stones to make them more efficient, then to using them to kill, then adding a stick to the end (like an ax type of thing), etc. So in short, there's no way to say. Humans aren't the only ones to use tools either. There are ravens, chimps, finches, etc. that also use simple tools.
Were there only one group of monkeys or three?
well, all hominids (including modern humans) are apes, NOT monkeys, and there have been quite a few lines of hominids (homo erectus, neandarthals, the hobbit, etc). All but one survived, and that's because of various reasons... I think neandarthals were outcompeted by modern humans right?
Why there are hundreds of type of butterflies or dogs or fishes or snakes and only a single type of humans?
first of all, you're totally misrepresenting it. "butterflies" isn't just one group of organism, it's an... order? (domestic) dogs are all the same species, etc. If you want to compare them, you have to say that there are many kinds of butterflies, dogs, fish, snakes, and primates (which includes humans). There are also a couple of species of apes (which also includes humans)
as for why there is only one species of human... for a lot of reasons. We are relative newcomers to earth, and we breed relatively slowly (compared to butterflies, dogs, fish, and snakes). The faster you reproduce the faster you can usually evolve. The other species of human were also killed off for various reasons... diseases, climate changes like ice ages and supervolcanoes erupting, and even other humans. If you hadn't noticed, humans are very aggressive even within the same species. Other humans were probably killed off by modern humans.