Need more help reading a pattern

[Dawndra88]

I am working on a sleeve for a baby cardigan. I am going to type what the pattern states and then I will ask my question:

1st row. Knit
2nd row. Purl
These 2 rows will not be referred to as st-st (stocking stitch).
Working in st-st (throughout) inc 1 st at each end of 3rd and every foll 4th row to 36 sts.

Inc 1 st at each end of every foll 6th row to 38 sts.

I am stuck on the inc 1 st at each end of 3rd and every foll 4th row and inc 1 st at each end of every foll 6th row. What exactly do I do to complete this? I was thinking that I will increase 1 st at the beginning and at the end of the 3rd row. I would then increase again at the beginning and end of the 7th,11th, 15th, and 19th rows. Is this correct?

Thank you very much!