I know nothing about my Benzhou YY125T-25?!?

I bought my Benzhou YiYing in 2005, with absolutely no prior knowledge of scooters. It being a chinese import means it is proving difficult to get any information on the thing, and the fact that my instruction manual got damaged in the rain also doesnt help! It has had a service since I've had it which dealt with the couple of minor problems it had. Now I have the same problem as someone else has already mentioned on this site, ie its very hard to start and you need to keep the revs high to stop it from dying. I realised when this started happening that I don't even know how or where to replenish my vehicle with oil (I thought this might be the problem). aaaaaaaah please help me, I am clueless!