To create a new project in AgentSheets, Go to the File Drop Down menu and select new project. You will then be prompted for a project name.
Finally you will prompted to define the size of the agent. The size of the agent specifies the amount of pixels both width wise and height wise the agent can occupy. You can select a size from the drop down menu or or you can define your own size. In AgentSheets, The biggest an agent can be is 128x128.
You can now add agents to your project by going to the File Drop Down menu and selecting new agent.