When I first published this pattern someone asked for my guidance on fitting the parts together.
At the time I was a bit busy having just returned from my holiday but I have now done some more diagrams to show how to fit each of the parts together progressively. I have used the colours as in one of my coasters.
The stars represent the joins. The black ones show when they are visible and the arrows show where they are when hidden under other layers.
As the original diagram showed the two thinner shapes are the ones to interleave first. They must go under and over exactly as shown. Join the ends.
Then you add one of the other two going under or over as shown. This will hide one of the joins.
When you add the last shape all the joins will be hidden. This time every under will be followed by an over.
I have updated the pattern in the original post.