When it comes to using the Topaz programs, there is no right or wrong order. It is entirely up to you on how and when to incorporate Topaz into your workflow. In general, it is encouraged to make your image as “clean” as possible before making any color, detail or special effect adjustments. This means using DeNoise and/or DeJPEG to remove any noise or image artifacts first, so you know that your subsequent image adjustments will be applied to a clean image.
After that, the program(s) you use depends on the final vision you have for your image. One that I typically do, which may work for you as well, is to use Topaz Detail last, adjusting any final intricate details. And remember, you can also run the same filter twice on an image to create stronger effects. If you are using multiple filters and know exactly what you want for that image, I suggest making a duplicate of your background layer and applying all of your filter adjustments to that new layer.
See the chart below for a suggested workflow (the new Topaz Clarity is placed in the second tier):
So in conclusion, the order you make edits in depends on the look you are trying to achieve. Sometimes a single edit can be made, while other times you might find it appropriate to use multiple programs and effects!