I have the loom ready to start my three Hygge blankets. I’m starting with #1 but realized I’m not sure how to read the pattern.

It’s 5” of vertical lines, then the same horizontal and then vertical again. What does that mean? I understand it’s light (natural) followed by dark and there’s an extra natural every 5. Am I changing peacock and lime?

Thank you!

I think you’ve got it. Natural flowed by dark. From the picture in the pattern it looks like after your 2.5” peacock you would use natural/lime for 5”. That gives you lines in one direction. Then use lime again after your double natural. That will make lines in the other direction. Then 5” more of Lime after the double natural.
Use peacock similarly for 15” in the middle. Then another 15” with the lime. All L/D of course.
Or create your own sections!
Hope that helps.

Why will that make the lines change direction? If I’m using plain weave and all I do is alternate lime and natural for 5”, add an extra natural throw, what makes it change direction?

That’s the nature of log cabin. Jane Stafford’s School of Weaving Season 3 Episode 3 is all about log cabin.
If you aren’t subscribed Google ‘log cabin weaving’; SweetGeorgia Yarns has a good photo that shows why the lines change.
Basically in one pick light goes under a light warp and over a dark so you get a light line. Next is dark under a dark and covering the light therefore a dark line. Remarkably when you double either the light or the dark the lines change because the light goes under a dark and the dark goes under a light. But a picture is worth a thousand words!!
Just try a bit and you’ll see.

Ok. Thanks so much. I really appreciate it.