Photo Retouching and Restoration is a subject, that could fill a half-dozen books, and still not touch on it all - matter of fact, it IS a subject, that has filled dozens of books.
Now, as far as the Tools, each is explained in pretty good detail in the Help Files. I would look at the various recommended Tools, individually, and see how each of those works. You will also want to look into the Clone Stamp Tool, and also Layer Masks, as they can be real "life-savers," when doing this sort of work. Ideally, you will want to set up a workflow with as little "destructive editing" (where the actual pixels in the original have been altered), as is possible.
Just off the top of my head, here is a partial list of useful Tools and functions:
- Healing Brush/Spot Healing Brush/Patch Tool (all under the same icon)
- Clone Tool (not sure if the word "Stamp" is still being used
- All of the Selection Tools (many are ganged under one icon)
- Adjustment Layers, and especially Levels and Curves
- Layer Masks (for many uses), and Brushes can be very useful for adjusting these
- Content Aware Fill
- Paths (for creating exact, and controlable Selections, starting with the Pen Tool, and then changing the Path to a Selection - or by making a rough Selection, converting it to a Workpath, and adjusting)
Actually, the list goes on and on, to include:
Heck, almost all Tools and functions can be useful, depending on what you have to do.
I am not sure if she's updated things, but this is a great PLACE to start. The concepts will be there.
Take this article for what it is: a simple one page primer (or starter guide) offering ideas on where to begin with Retouching and Repairing Images.
It is clearly not intended to be a step-by-step tutorial for the entire process (which seems to be what you're looking for)
There are thousands of other articles online, Adobe and others, teaching retouching and repairing images thoroughly.
There are also online video courses and books published on this subject if you want more in depth instruction.
InfiniteSkills author Andy Anderson has created a tutorial video on using the sponge tool to remove excess color saturation, specifically for Photoshop CS6: http://infiniteskills.com/blog/2012/08/adobe-photoshop-cs6-tutorial-repairing-saturation-w ith-the-sponge/