The whole purpose of having two strands is so you won't have 'strands crisscrossing on the neck hole.'
Sometimes you don't need to understand what you're doing. Follow the directions exactly as written, and you can understand it after you see it. I often say that reading a pattern all the way through and expecting to understand it all is like reading the instructions for putting together a bicycle. Unless you do parts A, B, C, and D first, you'll never understand parts E and F.
shoulder with strand bound off stitches shoulder with strand.
You'll work one shoulder and drop that strand.
Work the other shoulder with it's own strand. Nothing crosses.
You said yourself that you're a very new knitter. Trust me on this one.