Hi Rachel, 12 sts is telling you the total number of sts you should have at the end of that portion of the directions. It seems to me also that it should be 8 and not 12. Do you have a link to the pattern or the name of the pattern?
You can see a video for wrap and turn (short rows) under the Free Videos tab at the top of this page, Advanced Techniques. Yes, you will be turning as though you were at the end of a row.
Again, the 19sts is telling you the total number of sts you’ll have after you increase by one st from 18 (at least this time the total makes sense). When you repeat this increase 27 times you’ll have 46sts (19+27).
Post a link or pattern name if you can.