They have their ups and downs at pet centre with ladder-like structure on hills (10)

'they have their ups and downs at pet centre with ladder-like structure on hills' is the definition.
The definition suggests an adverb but the answer is not.

'like structure on hills' is the wordplay.
'like' becomes 'a la' ('a la' can mean 'in the way of' in French).
'structure' becomes 'esc' (I can't justify this - if you can you should believe this answer much more).
'on' means one lot of letters go next to another.
'hills' becomes 'tors' (tor is a kind of hill).
'ala' after 'esc' is 'escala'.
'escala'+'tors'='ESCALATORS'

Can you help me to learn more?