Tin returning father put rounds on (5,2)

'rounds on' is the definition.
Although both the answer and definition are verbs in their -s form, I cannot see how one could define the other.

'tin returning father put' is the wordplay.
'tin' becomes 'Sn' (Sn is the chemical symbol for tin).
'returning' says the letters should be written in reverse.
'father' becomes 'pa' (pa can mean dad or father).
'put' becomes 'sat' (both can mean positioned or placed).
'pa' written backwards gives 'ap'.
'sn'+'ap'+'sat'='SNAPS AT'

Can you help me to learn more?