앞에 8자만 그리자 in golf means "Let's draw the starting digit eight in my score card" It actually means"I want to get a score of eightysomething(80~89)" Let's assume tha you used to get a score of 90 ~ 99 in golf game. If you got a score of 89 one day, you can draw 89 in your score card. The 89 is a number of starting digit eight.

actually '자만'is not a word. '자' is 'character' or 'letter' '만' is 'only' or 'just' The meaning of the whole sentence is ' Just draw character 8 in front [of you].' I'm a native Korean speaker but it seems a bit hard to explain. Hope it's helpful!