Start with the question someone is asking at 2am, not the architecture diagram.
This is one of the sample essays that come with the Ledger theme. Write your own in Posts > Add New: give it a title, an excerpt (the line under the title), a topic (category), a cover (featured image) and the text.
Headings in the text make up the essay's "In this essay" outline. The reading time is counted from the text, unless you set it in the post's Custom Fields.
