2 questions about wrong installation cubase EL 8 update

PREMISE:
In 2013 I bought Cubase ELEMENT 6. 30 APRIL 2015 I bought the upgrade to Cubase 8 ELEMENT. Installed the update on the computer that I saw traveling two separate programs : CubaseE 6 and CubaseE 8. OK PERFECT

Last week I format the computer and reinstall all programs , but instead to reinstall Cubase EL 6 , I install directly Cubase EL8. When I enter the activation code that appears a mistake “No license on which upgrade” ( right! obviously I have to first install CubaseE 6 , and activate then install the update to cubaseE 8 ) .
MY 2 QUESTIONS ARE :

  1. I uninstall cubasE 8 , install CubaseE 6 , the active , install cubaseE 8 , the active. Is this the right procedure ?
  2. At this point I will have 2 cubase. Can I uninstall ONLY cubaseE 6 to make my system more efficient ?

thanks for reply

no one has had the same problem?
HELP !!!

RESOLVED

https://www.youtube.com/watch?v=ctJ9Jsjh2oU