It sounds like you added a deeper sink, which means the drain in the wall is now too high.
If you have a disposer, I imagine that the lower part will be underwater now. I like to cut into the wall and lower the plumbing there when a deep sink is installed.
As far as the faucet goes. Normally hot is to the left, cold on the right
And if the faucet handle goes front to back, Hot toward the wall, and Cold toward the child hanging onto the handle from the front.