Updated documentation

Author: paulorb

docs/getting-started/quick-start.md

@@ -25,4 +25,49 @@ is performed, write operations are ignored.
 
 
 ## Custom Simulation
-To be documented!
+The simulation can be customized by providing a configuration (in XML format) to the simulator. This is an example of configuration:
+
+```xml
+<?xml version="1.0" encoding="US-ASCII" ?>
+<device ip="0.0.0.0" port="502">
+    <configuration initializeUndefinedRegisters="true" initialValue="0">
+        <registers>
+            <register addressType="HOLDING_REGISTER" address="14" symbol="RPM_MOTOR">500</register>
+            <register addressType="HOLDING_REGISTER" address="10" datatype="FLOAT32" symbol="TEMPERATURE">-12.5</register>
+            <register addressType="HOLDING_REGISTER" address="0"  datatype="INT16" symbol="RPM_MOTOR1">1</register>
+            <register addressType="COIL" address="1" symbol="RELAYON">1</register>
+            <register addressType="DISCRETE_INPUT" address="0" symbol="RELAY_STATUS">1</register>
+            <register addressType="INPUT_REGISTER" address="0" symbol="RPM">1</register>
+        </registers>
+    </configuration>
+    <simulation plcScanTime="1000">
+        <set symbol="TEMPERATURE">2.0</set>
+        <set symbol="RPM_MOTOR">15</set>
+        <delay>500</delay>
+        <set symbol="RPM">1</set>
+        <delay>500</delay>
+        <set symbol="RPM">0</set>
+        <delay>500</delay>
+        <sub symbol="RPM_MOTOR">10</sub>
+        <delay>500</delay>
+        <add symbol="RPM_MOTOR">10</add>
+    </simulation>
+</device>
+```
+
+Sections **device** and  **configuration** are **mandatory** 
+
+## Custom simulation with docker
+For the custom simulation to work, the configuration file must be defined. 
+
+1. Place the configuration file in a folder for example *simulation* folder
+2. From inside the folder (cd simulation) execute the following command 
+
+```
+docker run -it -v $PWD/:/simulation -p5002:5002 paulorb/modbus-simulator-cli   -f /simulation/simulation.xml
+```
+
+
+## Device section
+Device section is used to configure the network parameters of the driver
+*TODO: define device section*