To do this just flash any MESH MODEL SENSOR application to th dev boards . in the configuration header file comment the client define and remove the slash from server model.
Turn on both the devices . Go for provsioning ,I have done this with STM32WB5MM-DK .Here is the process. Open a terminal like tera term or Hterm and then setup the port baud rate 9600 . After this click on reset and B1 together and release reset . Once you relese reset hold B1 and you will see the Blue LED blinks once it blink Check the BLE MESH APP now . On the right edge click on + and just get done with setting up both devices . Once added go into model section and then click on B1 on server and you will get tempreture on phone as well as client hold B1 for distance . Other important parts are simply in the read me file.