G'day Alex,
Find a club, & get an experienced pilot or instructor to show you & explain to you how to tune an engine, he/she will also check out your plane, if you have one, & adjust anything that needs adjusting, & then will fly the plane for you, & trim it so it flys straight, then you can start learning, with the best possible chance of success.
But the bottom line is GET HELP, you won't regret it.