How to upgrade to Apple Mac OS X Lion
1. Completely backup your computer to an external hard drive. Read this article from Apple for instructions on performing a backup.
2. Check that the backup works, using the instructions in the article above, and then unplug the backup drive
3. Run Software Update and ensure that your software is up to date. In particular, be sure to install the Migration Assistant update.
4. Open the Mac App Store and download Lion. The download is around 4GB – about the same size as an HD film.
From there you can follow the instructions for installing Lion. The process should take around 30 minutes. If you’re upgrading a laptop, make sure it’s plugged in to the mains. You don’t want the battery to run out during an upgrade.
