Instructions are on the volcano. Fill to the vinegar line with vinegar. Then top off with water to the water line. Microwave. Only issue is that you have to be careful on getting the top (the white part) properly secured or I could easily see someone spilling hot water on themselves taking it out if not. If your microwave is pretty bad like mine was, best thing is to microwave it once for 5 minutes, wait for things to cool down. Microwave again for 5 minutes. Everything cleans right up after that.Works as advertised. Dried on, crusted mess came off so easily after I used this in the microwave for 6 minutes and then waited until it had cooled some. Very glad to have it.Doesn’t really have a scent until you add the vinegar. ? But very easy to use! Works perfectly to help cut down on the elbow grease to clean the microwave! Definitely recommend everyone to buy one! When cleaning your kitchen, just add vinegar and water then pop in microwave for 8 minutes while you clean the rest of the kitchen.The volcano came in a plastic bag with absolutely no instructions. The only instructions involve the word vinegar and the word water on the outside of the volcano. It does not tell you how long to microwave it, and you also cannot see fill lines inside the volcano which make it very difficult to fill properly. I had to look up instructions online.Husband says, “whoever thought of this is a genius.”Works great and so much easier than anything else I have tried.There is no scentMakes cleaning the microwave super quick and easy!