I have a 5 minute video to which I'd like to add transitions. I use the blade to cut the clip, I go back to the arrow tool to put in a transition, I select cross dissolve, render, and when I play across the transition nothing happens! I try to make the transition several seconds, render, and it still doesn't show anything!
If you cut a clip and put cross dissolve on the cut you're not going to see anything. You're basically cross dissolving through one video back to itself. As each frame fades out it's being replaced by the same frame that's coming back it.
If you want to make a dissolve at a shot change you have to ripple the shots back to create handles so that you're going from one shot to another and not just back to itself.
See if this explains it for you and tells you want you have to do