Change oil can you tell me or help me find the bolt on my gilera runner 125 2 stroke to let out all the oil from the engine

It is a 2 stroke there isn't any oil in your engine perse, basically your bike either runs premix fuel or it has a oil reservoir that injects oil in to the fuel mix. 2 strokes mix fuel and oil together in the crankcase, that is why 2 strokes are somewhat smokey. The oil that is injected or in the case of premix is what is used to lubricate the engines internals. So you won't be able to change the oil by draining it out of the engine block. If it has an oil reservoir you will need to top that up from time to time.