Here's the thread for tutorials. Looks those over, if you're still having problems we're here to help. 

A lightsource is the direction that the light is hitting your subject.

this shows some examples

Yes.



My suggestion is use a first hand study of light. Go turn on a lamp and put something under it, study that, draw that.

Get the basic lineart done and post it in the WIP forum, he'll help you from there.

and a short attention span to your art in general. This is not helping you. You need to focus on a single piece first. Then get some critiques. THEN ask about shading on that particular piece.

I personally feel the tutorial that jal posted is a bit confusing, especially for someone who doesn't understand what a lightsource is. Majority of it is fine, but there are a few examples that don't seem to fit, ex. the side light, and pillow shading.

For the Side light, why are only the goggles lite when surely the right side of the mask would show this as well.

Lastly for the pillow shade and mirror (which I'm not very familiar with) only have the front piece of the mask lit up, and only gray..

Those are my only complaint of the tut. but this is coming from a good size newb myself.