Join Taz Tally for an in-depth discussion in this video Using the exercise files, part of Photoshop Color Correction: Dark Color Cast.
If you are premium member of Lynda.com, you have access to the exercise files used throughout this title. You'll want to download those exercise files and then place them on your desktop for easy access. Then all you need to do is just double click on the exercise files folder and then look inside. And in this case you're going to have two exercise files. These are starting points, the first one is the lighthouse working and then later on, after you've done your initial adjustment, you are doing another adjustment, you open up lighthouse working two file. And that just about it, in order to access your files.
If you are not a premium subscriber to Lynda.com, you don't have access to the exercise files but you can follow on from scratch with your own assets.
Want more information about color correction? Check out Photoshop Color Correction: Fundamentals.