Sweater pattern trouble for “ Rowan brushed fleece pattern book”

This is a part of a pattern for my sweater and I have done (). I read this bottom all together and I woundered if it was to be done at the same time and if so, how would I go about doing that. If you know, please leave a comment on how I would do it in a more simple way for me to understand. Thank you!

(dec 1 st at armhole edge on next 5 rows), then on 3 foll alt rows, then on foll 4th row at the same time dec 1 st at neck edge on next row, then on 7 foll alt rows.

Yes, both the armhole and the neck edge shaping should be done at the same time. If you call the next row, row 1, then dec at the armhole edge on rows 1,2,3,4,5, then 7,9,11 and finally 15. Dec at the neck edge on rows 1, and then 3,5,7,9,11,13 and 15.