I'm super frustrated because when I try to place a transition or any effect for that matter, between two clips it only allows me to only place it at the beginning of the next clip, not in between the clips. And it doesn't allow me to move the transition either. But the weird thing is that some clips allow me to put them in between them with the exact same transitions, but most don't, it's super frustrating.
Notice the little triangles in the upper corner of some clips on the timeline?
Those mean you are at the first or last frame, the end, of the clip.
For transitions to work they have to have more clip past the cut points. Some frames BEFORE the cut point will be used for the incoming clip, and some frames AFTER the end cut point will be used transitioning to the next clip.
Those extra frames are called "handles".
Where you don't have handles, cross-transitions don't work.