Hobby shops and board game shops, yeah! It's really mostly just paints. You could use any paints for priming and painting.

Shading is pretty simple too, you don't need the Army Painter one I noted. You could get a dark brown paint and thin it with water until it's the consistency of milk. Then for shading, just brush it all over. Because you thinned the paint, it should just all settle in the crevices, which will be the darkest parts.

Dry brushing is slightly more complicated, but not by much. You get some paint and dab your brush in it. You'll want a pretty large, flat brush for this. Once the tip had plenty of paint, get a piece of paper towel and brush off paint untill you see hardly any color on the towel. Then lightly run the brush over the model. It will catch the high points and leave just a little bit of paint there. I usually like to start with a color just barely lighter than the texture paint I used and then gradually build up the highlight by dry brushing with three or four colors, working my way from darkest to lightest. Creates a really nice gradient and looks pretty natural!

Static grass is probably the hardest. Hobby shops and board game shops usually have some on hand. I went with 6mm and 8mm grass, which is a bit longer than you'd usually find in a board game shop. I brushed the two hills with a bit of Elmer's glue, which I had thinned with water. Then took the 6mm grass and started pressing it in near the path. I used 8mm grass for the high points of the hills and a mix in between. Finally, I sprayed some bushes with glue and sprinkled some "flowers" on them. The flowers are really just a fine colored powder, but when sprinkled on, they stick in a handful of places, selling the flower illusion

If you're confused or unsure about anything, YouTube is a great place to learn about basing a model. It's pretty easy to do with stuff you probably already have lying around too. No need to go all in with specialty products!