To change only your own time zone, click on your name at the top right. In the drop down menu, click on My Account.
Make sure you are in the Account tab.
Scroll down to Language & Time Zone and use the drop down to change your time zone.
In the event that an admin has a different time zone than a user, the admin's time zone will be converted to the time zone that the user has set. For example, if you have set a course to become available at 8:00 AM PST, any user in the EST time zone would have the course available at 11:00 AM EST.