When logged in as the Owner account go to your TIEIT Settings:
Under Company Settings, you will see the option for 'Manage Users':
When you click on that the user's list will appear to the right of the screen and you will see a column for Telephony:
Once you turn that on you can log out of the account and log into your account and in the top right corner you will see a phone receiver icon and that is the RingCentral icon. When you click on that you will be asked to sign in to your RingCentral account.
When you have logged in you can click that same icon the RingCentral side pane will show for you.