Confusion on Sweater pattern

Can anyone tell me what this means in this pattern?

On next round, begin the following pattern and repeat within brackets 5[4,0,0,0] times:
[R1: K from beginning of round to 1st marker, slip marker, K1, YO, K to one before 2nd
marker, YO, K1, slip marker, K to 3rd marker, slip marker, K1, YO, K to one before end
of round, YO, K1.
R2: K around in St st.]

I understand the actual pattern, but the part that confuses me is the first part stating repeat within brackets 5 (4, 0,0,0) times?

I haven’t started the pattern yet, since I want to make sure I am capable of reading it first!

thank you!

This pattern appears to be for 5 different sizes XS(S, M, L, XL).

The number of repeats corresponds to what size you are making. If you are making an XS then you must repeat the directions within the brackets 5 times. If you are making sizes M, L or XL you won’t be repeating the directions within the brackets at all. Just go on to the next set of directions.

That’s actually what I thought it meant, but to me it just didn’t make sense. Thank you though, for clearing that up for me, I think I’ll give the pattern a whirl then!!