Which color adjustment did you mean? if you want to remove any elements, you can goto Assets/Camera Interface folder, open each Cam Shutter compositions, uncheck “eye” botton on the left of the layer you want to disable

I tried everything, but my files change color afterwards as if there was a contrast setting

There are no color adjustment actually, only wave, blur, bulge and some trasnform effect. Maybe it’s corrupted? try re-download maybe

There is read me file of how to use the transition, if you need further assistance you can send me message via profile page

Yes, it’s easy to use simply drag and drop it above your photos or videos