See attached PDF for pattern.

I will be updating the pattern shortly to add this tip but am posting it here in the meantime:
If you are beginner (and even if you’re not), slight changes in your tension may make your blanket edges uneven, even diagonal looking. Two things help that:
-- Adding the border makes it less noticeable
-- Blocking! Yes, I too am a lazy blocker and the idea of blocking a blanket seemed silly and unnecessarily time-consuming but it really helped everything come out more rectangular in the end. So, for this project, if your edges make your blanket look more like a rhombus than a rectangle, blocking is the way to go.