It might be helpful to go to the Google search engine (click here) and enter "flat picking guitar," "flat picking instruction," etc. in the box there.

The technique of using a flat pick, or plectrum, (as opposed to using fingers or fingerpicks) is called "flat picking." There is such a thing as a flat-top guitar, as opposed to an archtop guitar, but I don't believe that "flat top picking" is a meaningful phrase. Knowing this may make it easier to find what you're looking for.

You may also find some previous discussions here on the Mudcat that apply. Enter something like "flat picking" in the "Digitrad and Forum Search" box and/or the "Filter" box, just above the list of thread titles.