But here's the basic overview:
Log in and click on your assignment. View the "upload" tab. Note the five-character code in the "Student uploads" box. This code is how the system identifies which assignment the student is trying to submit to. Provide this code to your students. They'll need to enter it when they go to the upload page.
Tell your students to submit their essays to the upload link: www.essaytagger.com/upload
Make sure you emphasize that each assignment will have its own assignment code. If a student submits a paper using an old assignment code, his/her work will end up in that previous assignment.