A form can be created only inside a folder. There are two options to create a new form. The toolbar link button can be used are one of the options or the context menu of a New Folder will give you the second option to create a new form. These options are explained below.
New Form ToolBar Link
New Form Context Menu of a folder
The add form option will take you to the AppForms Designer as shown below. More on the Designer is explained in the section AppForms Designer.