Marksman's target finally hit by stranger from the South (3,3)

'marksman's target' is the definition.
I know nothing about this answer so I cannot tell whether it can be defined by this definition.

'finally hit by stranger from the south' is the wordplay.
'finally' indicates one should take the final letters.
'by' means one lot of letters go next to another.
'stranger' becomes 'odder' (I've seen this before).
'from the south' is a reversal indicator (in a down clue, letters go up).
The final letter of 'hit' is 't'.
't'+'odder'='todder'
'todder' reversed gives 'RED-DOT'.

Can you help me to learn more?