B4R Question Module HC12

Esp8266 is 3,3V and this module is 5V enabled. Ok for the set pin which is connected to GND but Rx and TX must be connected with a Logic Level Translator (LLT). And at last of course GND with GND and Vin to 5V.

Don't forget that 5V has to be external. You will also have to use AT commands so it goes without saying that you will need to know the AT commands of this module.