When you access primary documents from a depository such as the State Records Office of Western Australia, it is good practice to record as many details as you can about the items you look at as well as the folders / files each item is stored in. Various pieces of information will be needed to construct the reference and it's better to have recorded more information than you need rather than not enough. 

As each document and the information you record about it will differ, please refer to the sections of the Chicago Manual that relate to, or can be adapted to, unpublished government documents  (see direct links below). Scan all these sections to gather information about formatting titles and dates etc. and then bring this together to construct the footnotes and bibliography entries correctly. Examples are provided in the sections linked below.