I caught a 6 inch long garden lizard on my driveway. It was injured and looked tired.
I put it in a small 8x8 cardboard box, lined the floor with damp paper towel, got some grass, 2 pea beans
a and 3 leaves and a twig, along with 5 rocks. I put the box under the overcast sun with a half of the box covered in shade. I want to help it, since it is injured, but I don't know what it eats, or if I should put it near a river or pond. It is 6 inches long, is a dark brownish color and has yellow and green spots on it's back. I tried to pet it with a soft twig but it didn't like it. I think it thinks I'm going to eat it. What should I do now? I don't want to touch it either because I'm afraid of picking up a disease or something.

Best to just leave it alone. You don't say what injuries it has but chances are that you're not going to save it. If it's not hurt too bad, it will get better on its own... if it's bad enough, there's nothing you can do.

Did you give it water?
Cut one side of the box off so it can leave.

I'm curious if what you actually have is a salamander. A spotted or tiger salamander to be specific. This would explain it's tired nature if you found it on a driveway.
You need to let this animal go. If it is injured you cannot fix it.

I'd be curious to see a picture if you could post one.