Here's an amateur stab - other responses will probably be much better, but...
The FIND statement returns a record or a record set. Once retrieved, you can "do things" with it. Try something more along the lines of:
Quote is in context somehow...
FIND Items where Item.Quote=ThisQuote
Quote.Note=Quote.Note + Item.ItemName (or Item.ItemNumber, or whatever...)
Actions taken after a FIND statement are taken on all objects returned in the query.
You may also want to insert a line break for each iteration of Items.
Worth a try.