Changing your password is a very simple process.
The first step is to click on your Username in the top right hand corner of your webpage, the position of which you will see circled below:
The next step would be to click on Edit Person:
You will then see an option at the bottom of the page to Change User Information, which will then give you further options to change password. In order to be able to change your password, you must know your current password, and input/confirm a new password of your choice.
Once you have completed the above steps, you should be able to log in to the system using your updated credentials.