Touch-up paint?

[AudiChan]

Has anyone bought a touch-up paint pen from expresspaint.com? That's the website dealer recommended me to go a factory color one, which I found my color code from the spare tire compartment. I'm just wondering how should I use it.

Some say apply it one layer, wait for 20 min., apply another layer and wait... until it's "thick" enough to match up the paint layer.

Also, wonder if I need "primer' as well...

Thanks!!!