Add to Chrome.
Click 'Add extension' above.
The installation process should take less than a minute.
Next, you'll Create an Account.
How do I logoff?
If you're logged into the LastPass website only (e.g. using a currently unsupported browser, or without the plug-in installed), you can just close the browser window or select your username near the upper-right corner, and then select "Logout" from the drop-down menu.
If you're logged into the LastPass plugin, click the LastPass icon, then choose Log Out, the last option at the end of the menu.