dec stiches confussion

I am cofuse about this line in a pattren which I am knitting
Dec 1 st next and 2 foll 4th rows, then on foll 38 alt rows, then on foll 19 rows
Please some one explain it

Welcome to KH!
Call the next row, row 1. Then you would decrease on row 1, 5 and 9. Decrease every other row on rows 11,13,15,17,19 etc until you have completed 38 alternate rows (row 85). Finally decrease every row for the next 19 rows.

Thanks a lot I appreciate ur help