The High Pass technique essentially finds edges and when coupled with a contrast blend mode like Overlay results in increased contrast at the edges giving the appearance of sharpening of the image. Smoother areas of the image are ignored which helps to make the process even more valuable. For example, High Pass sharpening of about 1 pixel on a portrait will sharpen the eyes and hair while ignoring the skin.
The effect can be reduced by using the Soft Light blend mode and/or reducing the opacity of the sharpening layer. Small images can use High Pass settings as low as .3 pixels, and some larger images can benefit from larger radius settings. Experimenting and analyzing the results is something the beginner needs to do to gain an understanding of how the process works.
Find the dialog under Filter | Other | High Pass and choose a setting appropriate for the image size. When you click OK the layer will turn gray with slight lighter and darker edges defining your subject edges. Change the layer blend mode to Overlay to start, and click the layer on and off to see the effect. This is best done with the image on screen at 50% or 100%. A 50% view more closely shows the result as it will appear on a print. Edges you would prefer remain unsharpened can be masked off if needed.
A full article explaining the technique with illustrations is on my Learning Page (see link at top). Check in there (refresh your page if needed to get the latest version).