How to acquire a profound knowledge of your subject (4,6)

'how' is the definition.
Both the answer and definition are adverbs.
Maybe there's a link between them I don't understand?

'a profound knowledge of your subject' is the wordplay.
I cannot quite understand how this works, but
'a' is present in the answer.
'profound' could be 'deep' (synonyms) and 'deep' is found within the answer.
The remaining letters 'redly' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...

'to acquire' acts as a link.

Can you help me to learn more?