While searching the web for germination techniques on ugni molinae, I stumbled on garden.org. This website offers great pictures and some info about the species too.

My question is, how much light do ugni molinae seeds need?

I temporarily gave up searching for the answer and went ahead and started six in a bedroom dresser lacking total light and another six near south facing window.

You may not get an answer here as it's unlikely that many have tried the seeds or if anyone on here has, they may never see this thread.
I have one but I just bought mine as a 4" pot and it's a couple feet tall now.

And hope you do find other useful areas on this site!

Welcome! You've found a wonderful group.
I had to look up the plant. There isn't much out there about seed germination. I only found this:

"Seeds are fairly slow to germinate, usually taking several weeks or a few months."
My guess is that your seedlings in your window will do the best. If you have a heat mat, that would help the germination.