Is the below sentence appropriate for a signboard placed in a self-service food court?
Please return here tray when you have finished eating.
1)Which word order is correct? 'Please return here tray' or ' Please return tray here'.
2)Is it also possible to say 'when you finished eating' instead of 'when you have finished eating'?
You don't need to bother with "When you have finished eating". Some people put their plates on the table and put the tray back before eating so you can have a sign which just says "Return trays here please" or "Return trays here. Thank you."
Remember - correct capitalisation, punctuation and spacing make posts much easier to read.