Once you have wrangled it into Paperspace, and set the location as suggested, check and make sure that it is on the appropriate layer.
This would also be the correct time to check a few other considerations, such as Dimension Style or styles you might generally favor,
default Layers that you might wish to include in your new Template, current Text style, Leader Styles, etc.
Personally I would also make sure that my Current Layer was set to 0.
Once you feel pretty good about it, SAVEAS .DWT and give it an appropriate name.
Should you want to make this your new Default QNEW drawing, that can be done as in the screenshot.