Check your preview to see which areas have been selected. Experiment with this selection feature. Of course, the results are not always predictable, since you are working with shades of color, but that is what can make it an exciting selection feature, and very useful if you are trying to customize color adjustment. The image at the left was created by selecting only the yellow from the flower image. I then loaded the selection in the new document and filled the selection with black.
Masks are selections and the two articles work hand in hand.
So now you have the basics of Selection tools in Photoshop. Paths is another very useful tool for creating selections, but I will be handling that topic separately in the near future. We will move on now to editing your selection boundaries. Photoshop does offer many post selection choices, and you should be very familiar with each one. Getting a good selection is most valuable when you can manipulate it to do what you require.