They owe money on a hill in Beds, perhaps (7)

Here is my best explanation:

'they owe money' is the definition.
The definition suggests an adverb but the answer is not.

'a hill in beds perhaps' is the wordplay.
'a hill' becomes 'tor' (tor is a kind of hill).
'in' indicates putting letters inside.
'perhaps' is an anagram indicator.
'beds' is an anagram of 'debs'.
'tor' put within 'debs' is 'DEBTORS'.

'on' is the link.

Can you help me to learn more?