I don't know much, but I do know:
1. with true HDR you need multiple exposures of the same shot (ie tripod, three shots, three shutter speeds).
2. most people use dedicated HDR software, either a PS add-on or independent software. Not sure how easy it is to do with basic PS.
A lot (most?) people use a technique called tone mapping to achieve results somewhat similar to HDR. That is easy to do and you only need one exposure. look for a Youtube video on how to do this in PS.
Personally I think HDR looks fake, but it does make the image "pop" on a monitor.