Windows 8 google account on mail app?

How do I add my gamil on the mail app. I have googled and you can, but its wanting me to sign in with my Microsoft account. Do I have too, I just want to use gmail.
open up the mail app and then click on the 'Charm', settings (obtained by placing cursor top or bottom right then click on the cog wheel). Near the top you'll see Accounts listed, click that and then add your account.

Going back to the sign in with a microsoft account. It does give a different side to win 8 if you get your self a hotmail/outlook account (otherwise known as a Microsoft account) You'll be able to use the sign in for windows 8 so your always synced with your files plus the account will grant you further access to other microsoft goodies like messenger etc.
You have to actually have the mail app open and use the Charms Bar while on the Mail app. Charms Bar, Settings, Accounts