davinci dont show videos on timeline and dont play them

I'm new user of Linux. I have Mint. I wanted to edit my video using Davinci. After following few tutorials it's finally on my computer, but now I can't play video inside of it and it doesn't even show frames of that video. I used ffmpeg to convert my files into mp4 (didn't work), and mov. Still not working. Please help I dont want to use kdenlive because it sucks. EDIT: I have OpenCL