Schematic diagram. Please help!

[DerStrom8]

A small, very weak transmitter will probably be okay, but if you're looking for any serious power (transmit more than, say, 50 feet), you'll need a license. At least contact your local authorities and let them know what you're trying to do. Have them contact the FCC to make sure you don't break any laws. You have to be very careful with transmitters.

 

[audioguru]

This article? https://www.electronics-lab.com/projects/rf/001/fm4.gif

No.
That is the first 4W Greek FM transmitter. The one you are using is the second one which is here: https://www.electronics-lab.com/projects/rf/006/index.html