Update modbus_tcp.md

docs/modbus_tcp.md

@@ -5,6 +5,7 @@ This is the documentation of the Modbus-TCP task
 - [Table of contents](#table-of-contents)
 - [Initialization](#initialization)
 - [Usage](#usage)
+- [Guide](#Guide)
 
 ## Initialization
 The Modbus task is initialized in the main function.
@@ -14,4 +15,17 @@ modbus_init();
 ```
 ## Usage
 
-![QmodMaster.exe](./img/QmodMaster.jpg)
+![QmodMaster.exe](./img/QmodMaster.jpg)
+
+## Guide
+
+- Set qmodmaster to tcp mode
+- Set IP of device
+- Set the device in multiple register mode
+- Connect with the board
+- Fill in the data as in the example
+- Send the data
+
+## Extra
+
+The start addres is ignored and the timeout warnings arne normal because there is no response from my code back to QModMaster.