To update general account details such as name, email address, etc, click on your avatar in the upper right corner of your ZenCast dashboard and select "Your profile":
The new page will open up automatically on the "Your profile" tab:
Here you can edit your name, email address, and time zone, upload or change your avatar, and further down the page you can update your password.
Remember to click "Update details" to save changes when you're done!