You do have to be careful to use the right oil. It has a wet clutch and you have to use the right oil.
The one picture is not enough to identify the machine. A front and rear picture could help. It looks like a 2001-2003 machine
possibly a 375cc.
As far as oil is concerned, you likely can't go wrong with a 10w40 (MA in the specifications) suitable for motorcycles in the engine and a 75-90 hypoid oil in the differentials. According to other forums on engine oils avoid the "Energy conserving" oils. They have friction reducing additives that can screw up wet clutches.
Has to be there look on the frame on the front end and on the swing arm also. It is most likely on upper left frame under the fender. Take a piece of sandpaper if you have to but it's there.