Short answer, as I said above, is Photo Shop has a huge amount of ones and zeros. Your photo may be a photo on your screen or when you print it, but to your camera, computer, PS, and printer it is data. A series of ones and zeros that all of them use to work together to give you a visual digital representation of what you saw in the viewfinder.

PS is a series of programs in one package to read more of your data and use advanced algorithms to decide what the tones, hues, light and shadow areas, texture, saturation and, well everything that you see in the photo.

RAW gives the programs more data to work with than jpg.
I pulled one of my photos at random. In RAW it is 19.5MB converted to jpg it is 398kb quite a loss of data.
PS has more programing to use that data than Lightroom.
Are you toneing your photos for true color? Do you set a white and black point then bring up the mid tones? Are your skin tones numerically correct? Do you work in CYMK profiles so that you can send your photos to a printer and have them print the same as what you see on your screen?

Probably not, the huge majority of people don�t, and don�t need to. They want to get a reasonable representation of their photo on the screen or on their printer. Lightroom is fine for that, better than fine.

Most people think of PS as a way to make big changes in a photo like removing a pole from behind someone (or maybe an ex altogether) When it is most usually used to make a series of small adjustments, a pimple from the brides nose, slight whitening of the teeth, an odd light reflection from somewhere across her veil. Removing blood shot eyes from the groom leftover from the bachelor party last night. That kind of thing.

PS is also about bringing out what is already in your photo. Bringing up shadows or bringing down highlights to make your photo better. Dodging and burning to bring out detail is as old as photography. Ansel Adams said if photographers could see what he did in the darkroom they would cry, but his photos are the standard of dodge and burn.


Links, man you can get PS help everywhere (lightroom too)
Start at the source https://forums.adobe.com

Google youtube for PS or LR tutorials, plenty of them there.

If you want serious training go to lynda.com. It is a pay site and for good reason. Well made online classes in what you are looking for.

Hope that is some help