i have been working to a pattern of 16 rows, you do 16 rows then another 8 before continuing in stocking stitch on row 5 of pattern make 1 at the start and end of the row , now the pattern says working in st-st continue inc as set i only need two more stitches do i knit and then inc on row 5 of my st-st thank you

Its hard to say for sure without seeing the actual wording of the pattern, but it sounds about right to increase each end of row 5 as you have said.
As its only 2 stitch increase and at the edge and in stocking stitch I wouldn’t think that it would make a massive difference to the overall project if you are out by a row or two so long as it is a largish item such as a sweater (not a small stuffed toy for instance or doll clothes where the difference of 2 stitches would have greater impact).
If there are matching parts such as if this is back and you will make the front similar,army or if this in one of two sleeves, then you need to make a note of wher you put the increase on this piece so that the other component matches it. When seaming an item the increase rows are a good place to help you line parts up so its would be better to have them matching.