Significance of applying to a specific round of admission?

Hello,
I am just starting with GMAT preparation so please bare with me for my novice question.

I intend to do MS in corporate finance. I saw different rounds with dead lines on different university web pages. Also talked with few admission officers from 2/3 colleges and they said if you apply to round 1 your probability of getting admitted is high. So I was curious about the significance of applying in different rounds.

Also does it have impact on getting scholarship?

Thanks in advance,
Shilpa