Imposition Wizards saves your current layout when you close it, so you always return to your latest project. This is OK when you do the same layout all the time, but for different layout we have presets.
Use the button at the top left corner of the Imposition Wizard window to display presets menu. Presets are pretty much like project files, you can save the current project, or load a previously saved one.
You can use presets on another computer if you like, simply click the Open item in the presets menu, and then click the “Folder” button there in order to see the folder where presets are stored. Copy the one you need to another computer to use it there.