Please make sure that Origin is added to the safe list of your firewall and antivirus software, also check that the required ports are open: https://help.ea.com/article/connection-issues-with-origin#1
The game has already been added to your account, check out your games library by clicking "My Games" in the top bar of your Origin client. From there you can install the game. You could also start the installation from disc by running the setup file from the game disk (make sure you log in with your Origin account so it won't ask for the code again)
If that doesn't help it would be nice if you could give a few more details or maybe you could post a screenshot of the error message you are seeing.