I don't understand how to open it so that bulb can be replaced. It has no screws. Tried to move white dome anti-clockwise but does move at all.
Looks like ones I have that are springs/clips holding it. Does it turn when you turned it?
If so, you might just have to shift it over a bit, and pull down carefully.
ps. I'm trying to find an example with images of how they fasten online.
I have this light fixture. If you can see the lip of the fixture as it meets the ceiling, you will see 4 small wire clip edges sticking over the lip of the glass housing. Do NOT mess with these, I mention them as verification it's the same fixture.
The trick is simply to pull STRAIGHT down. There is a metal bar that will pull down too, that the bulbs could get caught on and crack, so be careful as you pull down. The fixture will NOT pull off, just pull slowly until fully extended.
I had quite a few bugs on the lip on the outside of the fixture; if you tilt it, debris can spill. Good luck!