You can test your repairs without replacing everything into its protective cover first. This can save you some frustration when it doesn't work on the first try, but requires a bit more caution when handling the circuit board.

Long press the central button on the circuit board to turn it on. Does the red LED blink on?

Does it connect to your device?

Attach the speakers and try to play some audio

Attach a charger. Does the charging light come on?