I am not certain from the images what is your exact difficulty. One image is asking for the location that the file should be saved and the other is asking which format.
I suggest that you set up the file saving preferences. Click on the large red "A" icon in the upper left and at the bottom of the menu- "Options". Then go through the tabs and choose where files are saved, the backups go and so on.
I set up my default format for everything (AutoCad 2013) always make a folder in Windows Explorer for every project with a subfolder for ACAD, 3Ds models, Revit files, Images, documents and etc.
If your problem is something else, please write again with more more detail.