Flashing a BLE in UART


I would like to know some information about UART.

I have a MSP432 microcontroller board. And a BLE breakout board. I I would like to flash a firmware in to BLE.

I have connected BLE to microcontroller board in UART.

Otherside microcontroller board is connected to USB port of a PC.

I am using keil microvision 5. I have .hex file which is to be flashed to BLE.

How can i achieve this?. Thank you.