Can someone explain wgc?

So I'm new to golf betting but can someone please explain this tourney for me so 64 golfers 16 groups 4 golfers per group only the winner adavances right? But what if there's a tie? And is the first Rd only 18 holes?

If two or more players are tied at the top of the group, there is a sudden death stroke play tie-breaker played to decide who progresses. Each round players play a full 18-holes unless they win earlier in the round then match ends.

@SixGod

 Ty sir/mam