In the spreadsheet view, do users need to upload labels as a text file to then assign them to items? I work with Quill.org, a nonprofit edtech tool that helps students improve their writing skills, and we do a lot of labeling work now where we may need to assign say one of 20 labels to 1,000 responses at a time. I uploaded some sample data, but didn't understand how I could quickly assign labels to my content. Please let me know if I'm missing something here.