How to Read a Weaving Draft
The key to understanding a weaving draft is to imagine that you're hovering above your loom and looking straight down at it.
How it Relates to Rigid Heddles
First you have to realize that a rigid heddle is a simple shedding device that produces only 2 sheds. Shed #1 is the UP SHED and Shed #2 is the DOWN SHED. The slot threads never move, they are always in neutral. It's the threads that go through the holes (the heddles) that allow for the under/over required to weave something. By raising the threads in the holes above the slot threads, that gives you the first shed (the same as shaft #1 on a multi-shaft loom). By lowering the threads in the holes below the slot threads, that gives you the second shed (the same as shaft #2 on a multi-shaft loom)
A rigid heddle weaving draft will look something like this:
Reading from right to left, the top gives you the warp colors to put through the slots and holes (threading order). Reading from top to bottom, the right side gives you the weft color to weave by bringing the rigid heddle up and down.
Additonal detailed explanations of how to read a draft may be found on my sister site Joy Of Weaving.
This video is for multi-shaft looms but the same idea applies. The only difference is that your rigid heddle only has shafts #1 and #2.