Stick Christmas lights in new grotto, first of all (5)
I believe the answer is:
cling
'stick' is the definition.
(I know that stick can be written as cling)
'christmas lights in new grotto first of all' is the wordplay.
'first of all' says to take the initial letters.
The initial letters of 'christmas lights in new grotto' is 'CLING'.
(Other definitions for cling that I've seen before include "Hold, cleave" , "Clasp closely" , "have emotional attachment?" , "Hold on tightly, be dependent" , "Hold on as for dear life" .)