Mixing paint thinner with paint for touch up scratch

[Force]

This is my first time mixing paint thinner with paint so I can touch up on a scratch on my black Holden Commodore, but I'm not quite sure how to mix it and I was wondering if you guys could help. It's only a little sratch I need to cover up and the paint by itself is too thick. The paint I have is a small tin of Phantom black paint and the thinner is Aclac 20 acrylic thinner.

Thanks

 

[TAZ]

If it's "touch-up" paint, normally you don't have to mix anything with it.
It's normally an enamel and a little bit thicker than normal.

Or, unless of course it does state that you should add some reducer or thinner.