Where do I find more dust for the dust machine?

We're not sure how far you are, but you probably have something in your black bag that will open a new area, thus giving you more places to get dust. Do you have the putty knife to open the butcher shop? Have you been backstage at the theatre, past the piano? Have you gone in the front door of the manor?

It sounds like you are at the very begining. The dust spots on the first round are: Dock , suitcase, down the cliff on a rope, and area by machine. Once these are complete you receive a map. Which shows that another hidden object challenge has appeared back at the docks. At this point you should have enough dust.