For a variety of reasons, you may wish to contact another user. Doing so is simple. First, go to their user page. While at their user page, you'll see a link saying "talk page" on the top of their page. Click that link. That will put you on the user's talk page. You should then edit the talk page and leave your note. But: 1) Be sure you are on the talk page and not the user's page itself. You can identify the talk page by the fact that it says "User talk" and not just "User" at the top.