Once again, test it to see if it works. Use a multi-meter to see if power is flowing properly, or just put it in some sunlight and turn the radio on. Depending on how many amps your cells put out the radio should work, though if they're super cheap they might fall flat on directly powering your radio. That's ok, thats why we have batteries.
I used some double sided foam tape to secure everything inside. It keeps the circuit board from touching the metal tin area. If you're worried about shorts just put some electrical tape on the bottom of the tin.
Just be sure to line up your headphone jack and that inserting headphones doesn't unstick your circuit board.
Hot glue also works just fine.