First, let me say that you shouldnt do it, going by personal experience all kinds of drugs fuck with your mind and have long-term effects on the brain
well, magic mushrooms produce a psychedilic effect similar to that of LSD, but very much milder and the trip is shorter. It causes blurred vision, euphoria, you see waves, and also hallucination to a certain degree. they contain psychoactive chemicals such as psilocybin very similar to LSD in chemical structure.
there are different kind of shrooms, of which the Hawaiian is the most potent. For a beginner like yourself, i would recommend less than 2 grams to be safe, not that im saying you should do it, but thats a safe amount IF you are going to do it.
going by personal experience, i didnt have any bad feelings ever, but i had done all kinds of hallucigons before, if its your first time with hallucigons, do not take more than 4 grams since you dont know how to handle the trip, you could get paranoid and the whole thing could become a terrifying experience. Its all about controlling your mood and being easy going and relaxed, but you dont have to even worry about that if you take less than 4 grams
again, i say dont do it, escaping reality is not the answer