If you don't see Update Google Chrome then you're either using the latest version or the newest update hasn't yet rolled out to your device (this can take up to a week). Alternatively, you can select Note Now to restart Chrome at a late time. The tabs open when you updated the browser will relaunch as soon as the browser restarts. Orange means the update has been available for four days and red means its been at least a week since the update became available.
Whether you're a Mac or Windows user, the first step is to select the More icon (a vertical line of circles) from the top-right corner of Chrome.