The most common and most likely answer to this crossword clue is the 8 letter word DIGITISE
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Buddy explains!

The straight part
We know that "put on a CD" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case put on a cd = digitise.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does DIGITISE mean?
DIGITISE verb- To represent something (such as an image or sound) as a structured sequence of binary digits
- To quantize a continuous or analog value; to convert it into a discrete value
- To finger.