The CDM has five parts:
Part 1: Architecture
This defines the file naming convention and the general architecture. This architecture is very broadly the same as is used for DSR;
Part 2: Record Type Definitions
This defines the record types that are used to make up the four file formats in Part 3 of the standard and those used for the discrepancy formats in Parts 4 and 5 of the standard;
Part 3: Basic Claim Detail Messages
This defines four profiles that enable licensors to make claims to licensees in respect of right shares of musical works the licensor owns or administers that were reported to the licensor by the licensee in a sales/usage report (usually a DSR); and
Provide all the calculation details behind the individual and aggregate royalty claim being made by the licensor in sufficient detail that the licensee can be confident in accepting the associated invoice for payment;
Parts 4: Reporting Record Discrepancies:
This defines a profile to enable licensees to report record discrepancies (such as structural errors or unsupported allowed values) to the licensor that sent the original basic claim message; and
Part 5: Reporting Overclaim Discrepancies
This defines a profile to enable a licensee to report to two or more licensors that an overclaim exists on a musical work as a result of receipt by the licensee of two or more basic claim messages, each making claims in respect of that musical work that add up to more than 100%.
The allowed value sets for the various parts of CDM are defined in Part 2: Allowed Value Sets of DSR.
More information on the various profiles is available here.