In order to program your Arduino Uno, Nano or Mega you'll have to install the OpenRoberta USB-Program first, to establish a connection between your computer and your Arduino.
You can find an instruction on how to download and install the USB-Program here.
The following instructions will help you to connect the robot to the Open Roberta Lab.
Now connect the robot to the PC.
The first time, it may take quite a while for the computer to find the pre-installed driver for this connection. Wait until the "connect" button in the program is activated and the robot symbol in the upper right corner lights up red.
The connection is now established.
In the Open Roberta USB program the robot icon is now green and the name of the robot is displayed.
Please prefer the built-in Serial Monitor.
The Serial Monitor in the Arduino IDE cannot be used at the same time because it blocks the connection when the program is transferred.
After you have connected your Arduino to the Open Roberta Lab you will find the "Serial Monitor" in the tab "Arduino", under the item "Serial Monitor".
With the "Serial Monitor" you can view the output you have output with the block "Show on Serial Monitor ...".
The outputs appear one after the other on the screen. By clicking on the dropdown menu in the lower right corner of the monitor you can set the Baudrate of the serial interface of your Arduino.
By clicking on "Delete output" you can delete all displayed outputs and clean up the monitor.