updated schema image and added prerequisities

README.md

@@ -27,21 +27,28 @@ Power on the Raspberry pi and finish the installation process. Log into its cons
 - connected keyboard and monitor
 - serial port
 
+Prerequisites
+------------
+Once you are logged into the `Raspberry pi` console update your system
+> `sudo apt update`  
+`sudo apt upgrade`
+
+and install `git`. It will be used to download the `dog-trainer` 
+> `sudo apt install -y git`
+
+Recordings must be edited a little bit therefore some audio processing tool is needed. Install `ffmpeg` which will do the job  
+> `sudo apt install -y ffmpeg`
+
 How to install
 --------------
 
-Once you are logged into the `Raspberry pi` console clone the `dog-trainer` source code into your home directory
+Clone the `dog-trainer` source code into your home directory
-> `git clone https://gitea.virtonline.eu/2HoursProject/dog-trainer.git --depth 1`
+> `cd`  
+`git clone https://gitea.virtonline.eu/2HoursProject/dog-trainer.git --depth 1`
 
 Go into the newly created directory
 > `cd ~/dog-trainer`
 
-Dependencies
-------------
-
-The recordings must be edited a little bit so some audio processing tool is needed. Install `ffmpeg` which will do the job  
-> `apt install -y ffmpeg`
-
 Configuration
 -------------