Adding an email account on ipad

.I need to reinstall a yahoo email account on my ipad. How can I do that so that it can be accessed through the ipad Mail app, rather than just through the Yahoo app, which I don't much like, because I'm used to using the Mail app. When I tried installing using the Mail app after entering the information it just told me that Yahoo mail was installed on the ipad, but didn't enable access to it