you probably want to learn to type first before you start trying to tackle painting a car.

the can of paint should have the mix ratio on it... it can vary from paint to paint....also it can be a matter of personal preference. I like to add a little bit more reducer so the paint settles flat, you just can't spray it in as heavy of coats or it will run.

i also like to add a little reducer to my clear coat to so its a little thinner and settles better.