In order to create a new empty datafile (.ddf2 file) in Datadynamic you can proceed in 2 different ways:

a) start Datadynamic Report normally by double-clicking over the DD icon

- once the pop-up window appear, select 'Create a new datafile'. 

- Once you click 'OK', another window will then pop-up allowing you to give the new file the desired name and locate it in the desired folder 

b) the second way is when you already have DataDynamic Reporter open, using an already existing .ddf2 file and you want to create a new empty one 

- Click on the DD icon on the top left corner of the screen, and choose 'New file'

- A window will pop-up, like in case a) allowing you to choose for a file name and his destination. Once you name it, click on 'Open' and you'll have your new created empty file.

PS: in both cases a) and b) don't change the file extension, every DataDynamic file need to have the .ddf2 extension.