Art setup in Illustrator
UV printing builds an image in stacked layers, and every one of those layers is decided in Illustrator before the press ever runs. The day is built around that file: separating gloss, matte and texture onto their own layers, placing white ink to build opacity over dark or clear stock, and using clear ink as a raised texture pass rather than a varnish.
Get the layer structure right and the press does what you drew. Get it wrong and no amount of press time will recover it.
Most UV jobs fail in the art file, not on the machine. Shops send flat single-layer artwork and then cannot work out why the result has no dimension, no opacity over dark stock, and no texture that repeats. You leave able to build a correctly separated white-and-clear layer stack, which is the part no operator can do on your behalf.