You see the following window when you clicked on Activate offline:

 

Enter your Activation Key here. The Computer Identifier will be added automatically. Copy it to the clipboard with the button. You will need the computer identifier for requesting the computer key.

 

Now continue reading in the How to get your computer key? chapter.

 

Enter the computer key in the Computer Key field and then click on Activate my license offline.

 

 

Click on Finish. The license wizard will be closed.