A reading log is typically hand-written using Cornell Style.
The purpose of a reading log is to concentrate the reader on the flow of the plot, the complexities of the characters, and to promote prior knowledge/prior experience connections.
The left column contains the page number and the sentence quoted.
The right column contains two or three sentences describing what the quoted portion evokes in the reader. The answer does not need to clarify the issue -- the reader can note that the quote is confusing, for instance.
In short stories with a full page of text three or more quotes are required. For a partial page of text one or two quotes will be sufficient. In longer works three quotes every five pages is expected.