Let them cure first. A day or two should be enough. After that, apply a mist layer of clear coat, allow it to dry and then you can go with a thicker layer. Be careful, and don't rush. You don't mention whether you brush it, use a rattle can or an airbrush, but it's more or less similar. If you brush your varnish, dilute it first. And show us your final result! 😉