how to use evolution as a mail client
 

what do i need before configuring my email client evolution for my yahoo ID?
do i need to create a mail server on the internet first?

First question is (and sorry if this sounds obvious to you) do you have access to yahoo POP servers? It's a paid service, I believe, so if you're using the free email service, you won't be able to check your email from Evolution.

Unless there's some crazy way to do it that I'm not aware of. Which is entirely possible. I'm using Thunderbird, so my knowledge of Evolution is not that great. But if it's like any other email client out there, you need POP access.

what, if i host a sendmail server on internet and make evolution a client of it to recieve and send my mails?

IMAP is paid subscription, POP is free.
 

i just don't know how to use Evolution in GNOME. need help.

But I know IMAP is subscription service, while POP & POP3 is free.

Thank you.

Yes, possible.
http://system.cs.technion.ac.il/Conf..._Evolution.htm