Musician with piano appearing in seaside attraction (5)
I believe the answer is:
piper
'musician' is the definition.
(piper is a kind of musician)
'piano appearing in seaside attraction' is the wordplay.
'piano' becomes 'p'.
'appearing in' indicates putting letters inside.
'seaside attraction' becomes 'pier' (I've seen this before).
'p' going inside 'pier' is 'PIPER'.
'with' is the link.
(Other definitions for piper that I've seen before include "Instrumentalist, solo or military" , "He who pays him, calls the tune" , "Military musician" , "Musician (paid for a tune?)" , "Musician sometimes paid (or pied!)" .)