Please explain how the laptop won't let you download it online?
The more you tell us the more likely someone will have a solution. Tell us the issue. Describe any messages that pop up or give us a screenshot. And share any solutions that you have tried that haven't worked.
ASC - Late 2012 Mac mini, macOS 10.13.3; Watch, 38 mm AL, watchOS 4.2.2; iPad Air 2 & iPhone 7+, iOS 11.2.5; TV 4th Gen, tvOS 10.2.5; Airport Express.