Noob Needs Guidance Hiding Damage

There are several different tools and techniques that can be used.  Here are a few:

• To get rid of the big brown blotches in the sky, try selecting each cluster with the Lasso Tool (Keyboard Shortcut: L)
• Once a cluster has been surrounded with the Lasso, go to Edit>Fill Selection and the following dialog box will pop up:

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•  Make sure that Content-Aware is selected in the Use dropdown and click OK.  The selected area should be replaced by some "white sky".

• Once the major blemishes have been replaced by some white, use the Spot Healing Brush Tool to remove the remaining dark spots.  You can change the size of the healing brush by using the square bracket keys ([  ]).  Use a size that is enough to surround a spot and click.  You can use the same tool to remove the dark areas on the white shirt.  Use a small size brush and click in different areas of the shirt.  If you get a bad result, use the Undo button (or Ctrl+Z) and try again.
• For the areas in the grass that have the discoloration, I suggest using the Clone Stamp Tool (S).   Once the tool is selected, you press the Alt key in a nearby good area of the grass and click on a discolored area.  The discolored area will be replaced by the sample you selected with the Alt key.
• To finish the restoration, I suggest using the Perfect Landscape Guided Edit which will walk you through replacing the sky.  You should be able to get something like the following:

Now having gone through all these steps, I have remembered that Elements actually has a Restore Old Photo Guided Edit which will guide you through using these tools and others.

Hope this helps.

[Moderator moved from Photoshop to PS Elements.]

Start with the Eraser brush tool. 

Sample the sky color first and put it into your background color palette.  See this short video for more details.

Hope that helps.