Learning Silk Shading/Long and Short Stitch/Needlepainting

This is totally in my humble opinion, but I think the best way to start to learn the above methods would be to buy or borrow from a library

"Beginner's Guide to Silk Shading" by Clare Hanham"

That'll get you started on the simple stuff. Just doing several layers of shaded stitches. You need that information - but it's simple enough to absorb, and have a go at one of the little projects over the lending period of the book from the library. Hanham is perfect for this.

Then Trish Burr's "Long and Short Stitch".

She has heaps of information about how to stitch different common shapes, how to do wedge stitches, shorten stitches to fit particular shapes, stitching unusual shapes, the proportion of colours to use depending on the shape - heaps of extremely useful information that I found out the hard way during my book cover embroidery that you really do need.

But I think that a total beginner's brain may melt if they start with the Trish Burr. It's more a book you'll need to have on-side to refer to frequently once you have a basic grasp of the long and short stitch concept and you want to sew some weirdly shaped part of a flower, or the leg of a cat or something. And the projects she has are more likely to take months.

Again, only my humble opinion. (an d I have no affiliation with either author. This is simply my recent experience)

Gotta figure out the camera so I can photograph the book.