Not Enough Extra Media Beyond Clip Edges To Create Transition

As many others have asked, why can't I add a cross dissolve transition (or any transition) in between my two clips? I have tried everything in every youtube tutorial and in every comment thread with another person asking about this. Nothing is working!

I need to add the transition in between my intro clip and my video lesson actually starting. Otherwise it is so abrupt. And it won't let me add anything in between the the of the intro clip and the beginning of the lesson clip! I tried dropping it directly on top of the clip and that won't work either. What do I do? Help!

Thanks!