When entering my 1099-SA forms, what does the statement "The corrected box is checked on this 1099" mean?

At the top of your 1099-SA form there is a box that says CORRECTED (if checked)

If your 1099-SA form has been corrected  then you would check that box.

Otherwise you leave that box unchecked.

Do I file the original incorrect 1099-sa too? Or just the corrected one 

If you received a corrected Form 1099-SA, Just enter the corrected one.