What techniques does Homer use to indicate the passage of time?

The Odyssey is comprised of 25 books broken up into six groups that denote a period of time. The first four books describe the adventures of Telemachus, the son of Odysseus; the second four books recount the wandering of Odysseus between the island of Calypso and Phaeacia; the third is written in first person narrative, and the fourth bounces back to the main narrative.

sorry for the typo, that was a total of 24 book; my mistake!