Hi! I draw on a drawing tablet without a screen too! The one thing to do is to just draw OFTEN, so you get used to the feeling of drawing on the tablet while looking at your screen. Decide if you like the pressure settings, and adjust them as you go. I personally draw VERY HARD (I feel that it helps me with stability) and often forget that fact when I switch devices or switch to traditional pencils. Learn keyboard shortcuts, since you have the benefit of a PC & tablet: it will make your drawing process way faster.
Second, any program is fine. I've personally used Photoshop before. I generally like to praise Clip Studio Paint as the comic maker's dream program. It's a paid program (with frequent sales as low as $15) that comes with endless user-generated free assets that you can download, like brush sets, gradient sets, image resources, and 3D resources.
Useful brushes are subjective. You generally will have / need a preferred:
1) hard brush - sketching, inking, blocking shapes, flatting, shading
2) soft brush - sketching, inking, blocking shapes, flatting, shading
3) textured brush - sketching, inking, blocking shapes, flatting, shading
4) airbrush - flatting, shading
5) Any other shape or softness of brushes are helpful, but the above would be the bare essentials.
