Firstly, What human evolution really means? Are we (humans) evolve biologically from apes/monkeys etc. or we (humans) were not apes/ monkeys but just having traits of them (apes/monkeys)?

And Secondly, If we (humans) were apes/monkeys before human than how is it possible that one different specie changes/evolves into another different specie according to biological para metres?

Hi,

Yes, humans (Homo sapiens) are evolved from a group of apes (the Homininae), which shared a common ancester with an ape species that was also the forerunner of modern chimpanzees, somewhere around 7-8 million years ago. Further back (maybe 9-10 million years ago), this common ancestor of what would become human-like apes and chimpanzees evolved from another ape ancestor, one branch of which went off to become gorillas. Further back still, the common ancestor of what would become gorillas, chimps and humans had anotehr branch that became orangutans an so on back.

This is obviously a very simplistic description of the main speciation events, there is plenty of good information out there: https://en.wikipedia.org/wiki/Human_evolution; http://www.britannica.com/science/human-evolution etc. but these again give a digested version. To truly understand human evolution, there are a number of excellent textbooks and journal articles that would be useful for you to read but the above will at least give you a start understanding the basic events and the processes of speciation.