Incubator mystery

My sister is looking after some eggs for her school while they’re on break, we brought them home today. They reckon they’re due to hatch today. Although she isn’t sure exactly how many days old they are she thinks they’re probably around day 20.

We have them in an incubator, but realised once we got them home that the egg turner is still in, and we’re worried about if taking it out now would drop the humidity too much.

We’re also unable to find any info on how to work the incubator properly, and the school didn’t tell us much because I think they’ve just forgot to take the turner out.

We’ve found out we’re supposed to turn off the motor before we try and take it out, but does that mean just unplugging the whole thing? It only seems to have one plug, and is unbranded, so I can’t find an instruction manual for it.

We suspect the red dial, but with not knowing what any of those parts do, we’re a bit scared to change any settings.