What is indirect DM addressing?

Indirect DM addressing involves reading the contents of a specified DM word and using it as the address of another word in the DM Area, e.g., to read the contents of the second word.

In a program, this operates as follows:

The constant 0000 is not moved to DM 0100, but rather the contents of DM 0100, which is 0500, is taken as an address in the DM Area and the constant 0000 is moved to DM 0500.