The structures are stained on the slide. We use it to identify mold. It can be tricky because the identifying structures take a while to form. The media of choice is potato flake agar, but as an alternative, sabouraud dextrose agar can be used, but the structures don't develop as well. If you're dealing with mold, it should be done in a biosafety cabinet, as some species like penicillium, aspergillus, cladosporium, etc can be VERY powdery and get all over, which you obviously don't want in your brewery.
Here is the process anyways:
First make a line of lactophenol aniline blue on a slide
Take fungal tape between index finger and thumb, and touch it to the mold. Start in the center of the slide and place the tape on the slide. avoid trapping air. Scotch tape will work as well.
LP tape mount