To change your password you must go to your account Settings, by clicking on your profile icon (at the left bottom of your screen).
Within Settings, go to Account → Profile and click "Change Password."
You will automatically receive an email, where you will have to select the "Reset password" button.
Choose the combination that you want and finish the process clicking on the "Reset password" button once again.
Signing in with Google? In Account → Profile, the Sign-in methods section shows how you access Routal: Password, Google, or both. For more information, see Sign in with Google.