Smashed harp and tray before student starts to produce grammatic combinations (12)

'produce grammatic combinations' is the definition.
I don't know anything about this answer so I cannot tell whether this works.

'smashed harp and tray before student starts' is the wordplay.
'smashed' indicates an anagram.
'and' says to put letters next to each other.
'tray' becomes 'salver' (salver is a kind of tray).
'starts' indicates taking the first letters.
The initial letters of 'before student' is 'bs'.
'harp' anagrammed gives 'phra'.
'phra'+'salver'+'bs'='PHRASALVERBS'

'to' is the link.

Can you help me to learn more?