Attempt’s sound by early settlers making percussion instruments? (9)
I believe the answer is:
triangles
'percussion instruments?' is the definition.
(triangle is a kind of percussion instrument)
'attempt's sound by early settlers' is the wordplay.
'attempt' becomes 'try' (synonyms).
'sound' indicates a 'sounds like' (homophone) clue.
'by' means one lot of letters go next to another.
'early settlers' becomes 'Angles' (the Angles settled in Britain).
'try' sounds like 'tri'.
'tri'+'angles'='TRIANGLES'
'making' acts as a link.
(Other definitions for triangles that I've seen before include "Three-sided figures" , "Geometrical figures" , "Percussion instruments" , "Three-sided shapes" , "Three-sided polygons" .)