Turn In for Google Classroom

I am new to Kami and am using the free version. I created a week’s worth of assignments for my students and posted to Google Classroom. Not one of my students have been able to turn it it. What am I missing? PLease help. I am on day 2 of question after question from my students and I don’t have the answers. I emailed Kami support, but haven’t gotten a response yet.