They are collimated at the factory and the prisms are glued in place, Glenn. Most of the time, the problem with these budget viewers is with the eyepiece holders. BTW I have the same model and was looking to adjust collimation myself but fortunately did not.
First, if you have eyepieces without undercuts, they generally work better in these types of binoviewers. The problem is that the eyepieces are not centered properly or are tilted slightly in the holders. The undercuts add to the centering difficulty.
Anyway, what I would suggest to try first is to set your binoviewer in the scope and the right angle prism/mirror. Then place your eyepieces in the holders and only tighten the grabbing rings very, very lightly. Adjust them to just touch the eyepieces.
In fact, if you turned the scope upside-down, they would probably fall out.
Then adjust your IPD, and take a look.
That fixed things right up for me, and I hope it does for you. As I said I use eyepieces with no undercuts, but you may be okay, if you place them in the holders and keep them loose. Not loose to rattle around, but have the tightening ring just touch each eyepiece.
Tightening them to a normal tightness will almost always throw them off and make it impossible to merge the image.
Most say say that the difference between budget brands and the high priced kind are not in the optical quality but in the mechanical build, especially with the eyepiece holders.
Hope this helps, Glenn!