Qidi x-plus compatibility -- newbie question trying to make covid ear saver mask parts

Hello, I am new to 3d printing. I had gotten a qidi 3d x-plus printer for my daughter for Christmas but unfortunately I need some help getting started. My daughter is 13 and would like to help the Covid effort by making “ear savers” for surgical masks. Not trying to make money just want to help … maybe we can make 50/week but hopefully anything helps. Trying to print this, but I don’t see the qidi x-plus on the model menu to have it sliced here. How can I get this going?

Thanks to all for your help!

https://3dprint.nih.gov/discover/3dpx-013765