My bad, I added the instruction when I submit the extra, but forgot to copy it to the wiki page
now i don't have it so i will write a draft here and will update the wiki later. (Planning an end-user guide in PDF to be sent as instruction)
1. Install "Google Authenticator" & QR-code reader on your mobile phone.
(for android i prefer "barcode scanner")
2. On MODX manager: Manage > Users, write click your own account then update.
+ You will notice a new tab "GoogleAuthenticatorX" open it.
+ Click show secret
(NB. you have to be a sudo user)
3. Open "Google Authenticator" on your mobile device, choose "Set up account", then choose "Scan a barcode"
4. Scan the onscreen barcode provided by "GoogleAuthenticatoX"
5. You will notice a 6 digits code on "Google Authenticator" mobile application changing every 30 seconds. (This is the code to be used while logging into MODX manager)
6. On MODX manager, go to System settings, "GoogleAuthenticatorX" namespace, and change "Disable 2-step verification" to "No".
7. If you have courtesy login enabled
(Best way to provide the secret) if you refresh the page you will be provided with the same QR-code and will be logged out instantly, if you did not perform steps 1 to 5 earlier, you will have only 60 seconds to scan that qr-code
8. On your next attempt to login to MODX manager you will notice and extra field "Autentication key", after entering your credentials, enter the code provided by "Google Authenticator" mobile application (the one mentioned in step 5) and log in.
Now MODX manager log-in is secured with Google Authenticator 2-step verification (1 time password, which changes every 30 seconds).
All Users who will attemp to log-in through the manager will be required to enter the Authentication key (if enabled), ONLY the first login after every secret reset allows a courtesy login (if enabled)
Any questions please do not hesitate to post here.