You can find any tool by the Menu Structure HERE: https://turbocaddoc.atlassian.net/wiki/display/TC20UG/Menu+Structure
You can find the menu location of any tool by name HERE: https://turbocaddoc.atlassian.net/wiki/display/TC20UG/Tools+Mapped+to+Menus
Regions
Available in TurboCAD Pro and Platinum only
Combines 2D closed objects to form one object, called a region. Any overlap between selected objects is removed. The results are identical to using 2D Add, except that this tool requires that the objects be selected first. When using 2D Add, you select the objects during the operation.