Litter Box Training a Kitten?

8 weeks is a young kitten and he probably needed more time with the mom which will normally teach the kitten to go in the litterbox. 10-12 weeks is better but people want to get rid of kittens fast because they're tired of feeding them and looking after them.
He should not run from you when you go to take him to the litter box. Do you grab him and plunk him in there, or do you gently scoop him up and hold him to you, then put him down and pet him?
Do you use a harsh tone of voice or say "No!" 8 week kittens are too young to understand why you do that. And don't chase him down.

You'll only end up scaring him about the box.
When your kitten has an accident, act as if it never happened. Don't scold the cat, it's pointless at this age. Clean the spot with enzymatic cleaner very well.
At regular intervals gently take the kitten to the box and put him in it. Scratch the litter with the scooper. If the kitten goes in there at all, pet him and then be sure to give him a little soft treat.
It won't hurt to have two boxes at first, one for the living area and one for bedrooms or wherever he's likely to be. I did this for my cat at first.

If you are harsh with this kitten you run the risk of training it NOT to use the litter box. Have more than one box and be sure the sides are easy for her to climb over. It can be helpful to keep kitty in a smaller space (bathroom or small bedroom) with her box for a few days until she gets consistent with using her box.

No longer than 3 or 4 days tho. Then be sure you have boxes in more than one place so she can get to one easily.