Habitrail for hamster

[Spinaroo]

Help- am new to this. Presently have a hamster( If i remember correctly its a Russian hamster- quite small. It's in a habitrail cage . Should I put the sawdust type stuff in the wee water pod too or will it just get wet. Not sure it wanted to come down the vertical tubes so have laid it more flat and it seems to be moving around exploring jut now.

Should I also put nesting material in the wee box hides hole? The pet shop already set it up with some in the carry case part.

It seems to have done the toilet in this particular nesting material-maybe because it didn't want to go down the tube. Should I replace the nesting material just now? Worried I stress it out with too much change at once.

Thanks if you have read this- I known it is Christmas Eve