What Salmonmac said. On the wrong side, you would just purl across with no increases. It sounds like the pattern is poorly written. If you want to, you can rewrite it so it’s understandable to you. Do this as you go along. You may want to make another sweater like this at a later date. You should be okay with rewriting as long as you’re not violating any copyright laws by sharing, selling, or publishing this pattern.
I have a small notebook where I will rewrite patterns into directions I can understand. Sometimes I simplify them my way or I’ll write down my little tricks and shortcuts to make knitting a certain article easier. I’ll also write down sizes and numbers of cast on stitches. Some things I make a lot and I’m sure I’ll remember them. But as a few months go by, do you think I can recall them? This is where that notebook comes in handy.
Mine is a spiral bound notebook maybe four by six inches. It tucks easily into my knitting bag and is portable. Any time I have a question about something, I know where to go. It’s all in that one little book. Simplifies things. You can also get small 5 by 7 binders with rings where you can organize everything, maybe with tabs and separate patterns into categories.