How to upgrade to Android Lollipop
On your Android device, go to 'Settings'> 'About Phone'> 'System Updates'. By clicking there, your phone will search for available updates.
If no update yet means you have to keep waiting, but could also be that because you appear Lollipop available. In that case, you will see a window informing you that a new version of Android. Plug the terminal, make sure you are connected to a wireless network, and click 'Download update'.
Downloading all the data you need to update your phone starts. Be patient as it may take several minutes.
When the download is complete, a window asking if you want to install the update will appear. Click on 'Update Now'.
Now do not panic: your phone will turn off and is normal. Below you begin installing the update, which can take several minutes. When finished, the phone will restart with Android Lollipop already installed.