Resources for the Town Sign will appear as random drops, but very, very rarely.
Only one teen can bee an Idol, and therefore your Teen Idol can use all the different instruments.
One type of instrument produces one type of notes.
After the first collection you have to
write 3 notes (30 min. each) on the keyboard after wich you recieve 1.000 XP
write 3 notes (1 hour each) on the bass guitar after wich you recieve 1.500 XP
write 3 notes (1½ hour each) on the drum kit after wich you recieve a TV Show Cameo ressource
write 3 notes (2 hour each) on the Electric guitar after wich you recieve a Radio Interview ressource
write 3 notes (3 hours each) by singing in the microphone after wich you recieve a Magazine Photoshoot ressource
You recieve 3 LP for a full collection.
For the full upgraded sign there is a possible bonus to the town revenue of §600.
Being very impatient, I've used a lot of LP's to level up.
AND WOW!!! BIG SURPRISE!!!, the teen Idol Mansion is realy not that expensive, IT'S TOTALY FREE!!! - Way to go EA/Firemonkeys

The Mansion raises town value with §1.400.000.
3 days to build (will probably be cut down) - I'm on it.