Moped Army

okay so at first i thought my transmisson dropped, but i found out it wasnt that (i dont think) .. now i opened both sides of the crank case to find nothing wrong at all .. now im at a hault, i dont know what else to do..

incase you dont know what happened, i was drivin along and stopped at a red light .. as soon as i went to go take off, i did nothin but rev the engine up to high ass rpms .. i thought my chain popped but nah, that wasnt it .. so im thinkn the clutch slipped or broke but idk.. where is the clutch located? so i can check to see if that was it .. or does anyone know what happened? i am so confused on as to what has happened, i cant find anything wrong within the crank case .. thanks for help in advance ..

p.s. i can provide pics if needed