Pencils and paper, etc., put on royal yacht initially (10)
I believe the answer is:
stationery
'pencils and paper etc' is the definition.
I can't tell whether this definition defines the answer.
'put on royal yacht initially' is the wordplay.
'put' becomes 'station' (I've seen this before).
'on' says to put letters next to each other (in a down clue, letters appear on others).
'royal' becomes 'er' (abbreviation for Elizabeth Regina).
'initially' indicates taking the first letters.
The initial letter of 'yacht' is 'y'.
'station'+'er'+'y'='STATIONERY'
Can you help me to learn more?
(Other definitions for stationery that I've seen before include "Materials needed for writing" , "Writer's needs" , "Various items in paper" , "The papers, etc" , "Writing material" .)