How can I wrap textures around a model?

Well I have a primitive of a rectangle, but I want to use it for a map I am making. I already have the vmt and vtf for it, but how can I get it to wrap around to the indiviual rectangle?

UVW Unwrapping.

It depends on the program you’re using to make the box, but there should be some sort of menu, modifier or otherwise something to facilitate unwrapping.
All unwrapping does is tell the model what part of an image a polygon should be looking at.

It’s like reverse-engineering a real model of a cube into one of those T-shaped nets, coloring it in and putting it back together.

It’s not magnificently easy on more complex stuff, but since it’s just a box it should take about 6 seconds.