Which bolt do I undo to change my engine oil?

Hi, I have a 125cc 4st piaggio skipper, I want to change my engine oil but theres no bolt on the bottom of the engine..? But there are 2 on the exhaust side.. Heres a picture, which bolt is the one to drain the engine oil?



Thanks for any help.

 

hexagonal one, the other one may be your oil filter. im not so familiar with the piaggio 4ts though.

 

your right, hex is oil, other one is oil filter

 

Ok cheers for the help