To see if you’re logged in, look at the top right of the browser window. If you see “Login” as the last item on the menu, you’re not logged in (see circled item).
Click the “Login”, which will take you to the login page shown next.
Fill in your username and password, click “Remember me” if you want, and click the “Log In” button. You will be redirected to the site’s home page, and the last item on the navigation bar should now read “Logout”