The way I approach this sort of question is to go through the text and underline/highlight - using three different marks/colours: 1) the organisational structures 2) the roles/people and 3) the technology. Then I start grouping together along hierarchical lines: an organisation X includes the following departments, etc. I also think about the boundaries - what is inside an organisation and what is outside, where are the boundaries of the system. In the example Systems Map, you can see that you have the conversion project as the main object and the residents and county legislators exist, but they are not part of the project.
The TOP diagram is the easiest to draw because you just focus on capturing and grouping separately: the technology, the organisational structure, and the people roles. Comparing the TOP diagram to the Systems Map in the example, you can question what happened to the Records Staff! Plus note the TOP diagram has more technology in it, and also more consideration of roles within people.
Note: case study shall be considered from the attached pdf file .. consider activity 1.2 in the pdf file as case study