I had the same trouble when I first started bandweaving, and decided that once I learned how to do it, I'd create some nice visual guides to fill in the gaps.
It's still a work in progress, and quickly spiraled out of control into a fully illustrated book (oops), but here are a few pages you might find useful that explain how plainweave patterns work with a rigid heddle:
Apologies if the wording doesn't make perfect sense, it's still a somewhat rough draft textwise.
As for the double slotted heddles for baltic pick up, I found this video super helpful when I was first learning how to use them:
I also have a post that very briefly goes over how to design your own baltic pick up patterns here.