The stuff on the bottom is too wet. Don't use it for plants until the bad smell is gone.

To do that, you might mix the entire pile now and then to help it compost.

Or you could remove the stinky stuff and begin another pile with it.

Compost needs to breath, so you ought to either work aeration into your pile or turn it every now and then to ensure that doesn't happen again. Also, too much water forces out the air.

If it smells, you add a carbon....newspaper, leaves, straw. Add enough until it's just like a damp sponge when you mix the pile. You generally need more carbon than nitrogen (newspaper to food scraps) so every time you add food scraps, spread some carbon over it.

It was probably too high in Nitrogen and moisture. That urine smell is ammonia formed from the N.

Your addition of paper should solve the problem.

You want to keep your compost mixed and full of shredded paper. The compost should be three parts brown (shredded paper, junk mail) to one part green (kitchen scraps)... and it should only be moist, not wet.

Keep mixing in dry shredded paper until you get rid of the smell. The compost doesn't need to be tossed, it just needs a bit of tweaking.