To harvest mushroom spores by making a spore print, you need edible mushrooms — any variety will do but, as mentioned, the gill types are easiest and most available at the local grocers. Make sure it is a mature specimen, one with gills readily apparent. Also, you’ll need a piece of white paper, a piece of black paper, and a glass container that can be inverted over the mushroom. (The purpose of two colors of paper is because sometimes spores are light colored and sometimes dark. Using both will enable you to see the spores regardless of their shade.)
Put the two colors of paper side by side. Remove the stem from the mushroom of your choice and upend it, placing the cap spore side down onto the two pieces of paper with one half on white and one half on black. Cover the mushroom with the glass container to prevent it from drying out. Leave the fungus covered overnight and by the next day, the spores will have dropped from the cap onto the paper.