Why and when the religions were created?

Which religions? There are hundreds. Some new, some old, some that aren't in major use anymore. You'll have to be much more specific if you don't want a 200,000 word answer.

Some would say that religions are Man's way of explaining the universe and life to himself.

the 1st part, why:

Coz people should know the way they can contact with their Creator, and know how to live the way they were created for.

There are religions God revealed to people, and there are religions people invented for themselves, and all indicates the nature that God placed in us, which is seeking Him and searching for His blessings.

the 2nd part, when:

right from the creation of the 1st man on earth, Adam who worshipped God as one god with no partner.

This is obvious when you revise the story of Abel and Cain, Cain killed his brother because God accepted Abel's sacrifice and didn't accept his, so he envied his brother and went to kill him.

So the story shows there were duties on every human to do as a part of his religion from the beginning of creation