From the version Library 4.2.18 290 on, to login to your cloud accounts you need to follow this path :

• from the Library page click onto the three dots in the upper bar on the right
• the PadMu accounts window will appear, clic onto the Cloud account you are interested in, to login to it
• complete the login process as asked by that cloud service
• after the login has finished, at this point the button will show "Logout"
• clic on "cancel" in the window to go back to the Library
• click on add files icon on the top, you will see that Cloud service icon available, click on it to access your files
• you are done !

Important : if you are a PadMu3, PadMu3LUMI and PadMuLUMI2 user, as far as Google Drive is concerned you need first to activate the Google Services. To do that, from the PadMu homepage, click on settings (lowest left icon), the click on "Application", click on "enable google play" and then sign in following the Google standard process ; in case of PadMu3, PadMu3LUMI owners please follow the instructions of the user manual. 

If you are a PadMuLUMI2 user , the process of activating the Google Services is far easier :

just click on "enable google play",  login to Google and after that, reboot the tablet.

Then go to the Library page and click on the add files icon, you will see the Google Drive option in the Add New File window.

Thank You