The Rigveda is categorized in the form of octads and book. The octads known as ‘ashtakas‘ and the book is known as mandal or mandala.
Ashtakas
There are eight ashtakas or octads in the whole rigveda, contains the verses or mantras, beginning from the first mantra “agnimile purohitam” and ending with the last mantra terminating with the words “yatha vah susahasati”
In each octads or ashtakas, there are eight chapters.
Vargas
In the whole rigveda there are total 2024 section or vargas