To sign up for, or sign in to, Hours on the web, go to hourstimetracking.com and click on either "Sign in" or "Sign up" at the top of the screen. Hours on the Web is a pro feature and requires a subscription.
Once you have signed in, bookmark your Hours site to make it easy to return to Hours. If you are using Safari, you can also drag the Hours tab to the left to pin it to your tab bar in a compact little icon that you can get to at any time. Nifty for getting to your timers quickly!