Songs will not load to the Deck

i have the demo version rn just getting into mixing and i have a controller that appearently only works with djay pro for some reason (so if someone can help me figure out why that is that would be great) but when i go to load a track onto either deck it just sits and buffers(?) and never loads the track even though the track is already saved on my computer. i would love for this to work so i can practice for the 15 days and see if i like it and buy it but I CANT EVEN LOAD A DAMN SONG