So you can upload the savegames from the PC, right? I was worried I had to remember every single thing I did in the previous two games :S
There is no upload feature . It pulls the results from your origin account and creates and export for you to use on any platform. I assume as soon as you boot up DA3 and put in your origin credentials it will grab the export.
As for remembering what options there is a long graphical story and you can change he options as you see fit. After the story you can fine tune it by going into the tapestry and selecting whatever you can remember. Mainly this would be companion stuff.