I managed to get mine back on with trial and error.
This is how I did it.
1) Clip crystal into gasket
2) Clip gasket on to case ensure you have pressed it down fully it should click into place. Ensure crystal is positioned correctly.
3) I then put on the retainer ring (You have to make sure it is the correct way around (The thicker part should be on top as this holds the Bezel and stops it from popping off. I used a Watch back press from eBay to get the retainer ring on (You won't be able to get it back on without the correct size attachment).
4) Ensure all screws springs etc are in place.
5) Lastly place the bezel on top and press it down with the Watch back press (Using the correct size attachment)
That should be it
My watch is back together again now but without a ceramic insert