search tool is just another info display mode. press search on the remote 3 times and then select mode and it will toggle between insert/replace/append/enqueue. keep pressing search at that point and it will switch between title, artist, genre, etc...

search for a song in insert will put the song you 'find' next in line to be played.

replace just tosses your current playlist and plays the song/playlist you 'find'

append i forget

enqueue just adds the song you 'find' at the end of your current playlist