I got charged with something i shouldnt be getting charged with i need help on what to do.?

one night me and my friends went to this kids apartment and we were all smoking weed and then the cops came right after we got done smoking there was a grinder on the table,zig zag roller, and a 16 oz. beer can and my friend had 3 grams on him and he admitted the grinder was his and my other friend admitted to the zig zag roller but the cops searched all of us and found nothing on me and they are charging me with 3 counts of small amount personal use of marijuana and 3 counts of use/procession of drug paraphernalia. what should i do?