Problems with yahoo mail.?

I bought a Toshiba laptop computer yesterday, the low end model satellite and when I go to yahoo mail it loads the oldest mail from six months ago and I can't find an easy way to get to the newest mail. I do not see a tab like on my other computer which has windows vista. Yahoo had a place where you could click on an arrow to take you to your newest mail and now I don't see that arrow.

This machine has windows 8, some what aggravating to get used to it. But I am plugging through. Will someone explain it like I am in first grade. I am very a d d. Thanks for your help.

Lenny