Coincides with cryptic solver tackling advanced puzzle to begin with (8)

'coincides' is the definition.
(overlapping is a kind of coinciding)

'cryptic solver tackling advanced puzzle to begin with' is the wordplay.
'cryptic' indicates an anagram (a cryptic or obscure order of the letters).
'tackling' means one lot of letters goes inside another (to tackle is to take possession of).
'to begin with' suggests taking the first letters.
The first letters of 'advanced puzzle' is 'ap'.
'solver' with letters rearranged gives 'overls'.
'overls' placed around 'ap' is 'OVERLAPS'.

'with' is the link.