Youngster of ten by the looks of it, brought over to see large drilling apparatus (6)
I believe the answer is:
oilrig
'youngster of ten by the looks' is the definition.
I can't tell whether this definition defines the answer.
'of it brought over to see large drilling apparatus' is the wordplay.
'of it' becomes 'oi' (this could be a standard abbreviation which I don't know about).
'brought over' is a charade indicator (letters next to each other) (in a down clue, some letters go above others).
'to see large' becomes 'L' (eg in clothes sizes).
'drilling apparatus' becomes 'rig' (I've seen this in another clue).
'oi'+'l'+'rig'='OILRIG'
Can you help me to learn more?
(Other definitions for oilrig that I've seen before include "Crude producer" , "drilling installation" .)