Ok, I’ve finally gotten the money and am about to order GZG’s Pirate Mini-Starfleet set. I’m still fairly new to this and need some advice (In return I’ll post pictures of the final product ) The models are cast metal.

I’ve done a bit of research and have got a list of things I’ll need:
Black Primer or Grey or White (I need to decide on one.)
Paints (I have Acrylics)
Brushes (Have them; might pick up a super fine one)
File
sandpaper
filler (have some but I might buy a better quality)

Is there anything else that I need?

It sounds like you have what you need.

As for the color of primer ... here’s what I’ve done in the past.

For a more gritty science fiction feel—black undercoat. Colors will be more muted, and any unpainted areas thus look like deep shadows.

For a more Star Trekky look—white undercoat. The colors on the ship will pop.