Learning to use the manual camera settings

When I've taken pictures of the chanukiyah in the past, I've usually been disappointed by how blurry the flames look. Photographing flames in a darkened room is apparently challenging -- it's not just me. I asked a question about it a while back on the Codidact photography community and got some interesting advice.

I've been experimenting this season. Here's one from tonight that came out decently well:

photo, 5 candles, window reflection

The camera settings were:

  • Shutter speed: 1/90
  • ISO: 1600
  • Exposure: 0 (I don't know what this means; it's a scale from -2 to +2)

The other settings I have available are named:

  • White balance: (scale of pictograms of sun, light bulbs, etc)
  • Interval(s): scale from 0 to 60
  • Focus: picture of flower, 25/50/75%, picture of mountain

I left those set to "auto".

I can make guesses (based on the scales) about white balance and focus, but "interval(s)" has me stumped.