You can use Outlook (in the Microsoft Office package) to read your mail. In Outlook, you log in with your Radboud account (firstname.lastname [at] ru.nl), password and multifactor authentication (MFA). This applies to Apple, Windows and MacOS devices.
If you do not have Outlook on your (private) PC or laptop, you can download this programme for free at office.com and log in with the above details.
Outlook Web App
You can also use Outlook online via the Outlook Web App. Go to Outlook.office.com. Log in with your Radboud-account/e-mail address.