If you need a Ignition battery then your G-62 is not a magneto engine so it must have a Electronic Ign. This should hand start .Get someone in your club that has experience with gas engines to help you at first.
Ign battery depends on how old the unit is. Older igns required 4.8 to 6 volts newer ones will work 4.8 to 8 volts. I like the Life battery for Igns.6.6 volts.You will need a good two stroke oil.Stihl or Redline are two popular oils. I use the oil I am going to fly with from day one.Hope I don't start a oil thread.Use engine instructions for oil and gas mix. I use 32 to 1 for everything. They may not use that much oil. What prop do you have for your g-62.? Did you buy the engine new ?.
If you are in a club that has a few gas engine fliers,pick the flier that flies time after time and does not have to screw with his engine. See If he will help you.This is a pretty big engine for your first gasser. Good Luck
BCCHI