Step 1: Prefer it
To kick off, use the top iMovie menu to access the Preferences option. Click on it to bring up the Preferences interface window.
Step 2: Tick time
Now you need to check the Show Advanced Tools button and this will activate the professional features that are normally hidden in iMovie.
Step 3: Drag and drop
As simple as it sounds, the first thing you need to do to create picture-in-picture is drag one clip onto another in the main editor at the top of the interface.
Step 4: Magic menu
As you let go of the clip a contextual menu will appear. On the list that presents itself, there’s no prizes for guessing which option you should choose…
Step 5: Here it is
You should now see one clip above another in the editor on the left and the picture-in-picture preview in the screen on the right, just like in the screenshot.
Step 6: Move it
You can drag the picture-in-picture along the original clip at any time to make sure that it comes in, and of course leaves, at the perfect points.
Step 7: Some sound advice
As you’ll have noticed from playing it back you now have two audio sources too. Use a right-click on the clip to access this menu and select Detach Audio.
Step 8: Separate sounds
The detached audio now sits at the bottom of the arrangement, which means that you can play with the levels if you want to keep it, or follow the next step.
Step 9: Bin it
Alternatively, you can make use of the Delete key if you want to get rid of the audio altogether. This leaves the original clip’s sound intact and untouched.
(Click on the image below to zoom in and view the annotations)