doc: added some configuration instructions in README

TSM_PicoW_Sensor/README.md

@@ -1,5 +1,25 @@
 # TSM_PicoW_Sensor
-Project using the PicoW board with VS Code, implementing a sensor application.
+Project using the PicoW board. It publish sensors values (humidity, temperature) to an MQTT broker.
+
+## Configuration
+
+You have to use the serial terminal to configure the board by sending commands.
+
+### Wifi
+
+```shell
+McuMinINI write settings.ini WiFi ssid "YOUR_SSID"
+McuMinINI write settings.ini WiFi pass "YOUR_PASSWORD"
+```
+
+### MQTT
+
+```shell
+McuMinINI write settings.ini MQTT broker "BROKER_NAME"
+McuMinINI write settings.ini MQTT user "USERNAME"
+McuMinINI write settings.ini MQTT pass "PASSWORD"
+```
+
 
 ## Build
 Project has `Debug`, `Release` and `Test` targets, using CMake Presets.