Have a go at carrying a salver (4)
I believe the answer is:
tray
'salver' is the definition.
(I've seen this before)
'have a go at carrying a' is the wordplay.
'have a go at' becomes 'try' (to have a go at something is to try it).
'carrying' indicates putting letters inside.
'try' placed around 'a' is 'TRAY'.
(Other definitions for tray that I've seen before include "Flat surface for carrying things" , "Carrier (for eg, crockery, food)" , "Flat utensil for carrying food" , "'It's used for carrying, crockery say (4)'" , "canteen item" .)