This is a multi-size pattern. When it says knit 5{5-7-7-7} rows, the first number is for the smallest size, and they go progressivly larger (small, medium, large, extra large, 1x, etc). Pick the number that coordinates with the size you’re working.
When it says “work even” in stocking st, that just means work all rows in stocking st without increasing or decreasing.
There should be another row of instructions though. So if you’re working on size small (for example), you’ll knit 5 rows in stocking st, and a row in pattern either before or after those. Then repeat those 6 rows 3 times, and you’ll end up with 70 stitches.
Then continue working in stocking st until the piece measures 7 inches, and end with a wrong side row so that the next row is right side facing.