Under the seat use a 2 stroke oil designed for air cooled motorcycles, Synthetic oil seems best. Do not use oil designed for weedeaters or chainsaws.
Use oil designed for motorcycle gearboxes for the filler on the engine. No more than 650ml. There is a sight glass near the bottom of the engine.
10 w 30 engine oil can be used in the gear box, providing it has no friction modifiers. Some people use auto trans type F.
Make sure you do the break in proceedure. Start the motor, let it idle to operating temp, switch off, then let it cool for 30 mins or more.
Do this 3 - 5 times, re tension head and jug bolts. Ride two tanks of gas at no more than 3/4 throttle, then let it rip.