Here's a simple sample. Here's a more complex version with sound effects.
The key to this project is to move the objects (text in this case) using the Event Pan/Crop and keyframes. DO NOT use the Generated Media Placement with keyframes.
In the Event Pan/Crop there is the Sync/Cursor button next to the keyframe timeline. Make sure this is turned on so that the cursor in the keyframe timeline is synched with the cursor in the main timeline and also with the video preview.
In the picture above, note that the synch cursor buttong is ON.
Select the first keyframe in the Event Pan/Crop. Get the text placed in the spot where it will need to be to interact with the video.
Click on the timeline in Event Pan/Crop of your generated media. Use arrow keys to go thru the video slowly to find the spot where you want to interact. The keyframe circled in red is where my hand was going to make contact with the text. Then I added a keyframe fairly close to the right (to make the text move fast) and dragged the text off the left side of the video.