Hello! The game should automatically import your S1 save for you, as long as you played through S1 on the same computer and haven't moved the savefile.
Thanks for getting back to me! For some reason, my S1 save file was in a folder called com.Company.ProductName in my Library, so I think S2 wasn't recognizing it? I tried running S1 again, and it created a new folder in the Library with a different name, so I dragged the save file into it and now S2 likes it :)