I found a second tutorial based on the this mama makes stuff on a blog called homemade by Jill which can be found here.
Basically the instructions are cut out 3 rectangles for your pattern - a waist strap, the connector, and a seat piece (may vary in size depending on child)
2 patterns of fabric (if preferred)
Cut out 3 rectangles in each fabric and 3 rectangles of batting to fit in between fabric pieces. Check their tutorials for further instructions as I haven't tried this out yet.
Below are some pictures from the blog homemade by Jill: