Knitting a sleeve

I am knitting a Sara’s Hatton pattern and I do not understand what the pattern means and would appreciate help:
Can someone please explain what this actually means:
Increase 1 stitch at each end of 5th and 3(2:1:8:10) following 6th rows, then on every following 8th row.

The instructions want you to increase at each end of the 5th row from the row you’ve just finished and then at each end of every 6th row. So you would increase on row 5,[U]11,17,23[/U] etc. The number of times to do the underlined increase is 3(2:1:8:10) depending on the size you’re making. So in the example I gave, there are 3 increases every 6th row which is for the smallest size.