If you don not have a Smart Phone, or if you do not want to use a Smart Phone, you can use alternative programs to provide the passcode needed for 2FA. A few of these programs are:
or any softwares that implements OTP standards.
So after installing one or more of the above programs you can proceed to go to a web page that helps you setup 2FA. For example, you can go to the Sterrewacht virtual desktop. When you access that page you are redirected to the new Observatory Identity Provider and presented with a login window.
After entering your account credentials you are present a QR code on the next page. Your computer programs are not equipped to scan QR codes, so you need to 'see' the secret key. For this you click the link
Unable to scan?
After clicking the link you will be presented a window that shows you the secret key in clear text. Copy this key and save it in a place where your program can use it. Then run this program to obtain a passcode (a six digit number). Transfer this passcode to the form. Note that the passcodes have a lifespan of 30 seconds, so you might need to regenerate a new passcode if the 30 sec. timeslot has passed.
Since you are now setting up 2FA for the first time, you may also type in a name for the device from which you are getting the passcodes. It is merely a tag for later use. Having filled in all required fields, you continue to
Submit the next form.
Now follow the steps from section Remaining Setup