What you need to know before starting your first project
Your 10 First Projects (Hero / UNO R3)
The 37 in 1 Sensor Kit
Learning Components
Your First 10 Projects With The Arduino/HERO Simulator
Code Like A Wizard
Wizard Coding

MacOS Installation 03 – Change settings

Because I am an unidentified registered developer you need to open the System Preferences and go to Security & Privacy. Under General you will see a message with a button ‘Open Anyway’. This will open the simulator application and allow to open in the future.