As the name implies, iMovie is primarily a video editing software. Yes, you may add image and audio files, but the main thing you will be working with is video. Before you can actually begin mixing and matching content, the first thing you have to make sure is that all that videos that you will need have been imported and can be seen in the Events Library and you have created a Project File. Open the project by double clicking the project name. If the project is empty, it should be blank. If you want to continue working on an existing project, it should now show the frames of the movie.
To starting working on your project, select the event that contains the video that you will be using. Frames of the different video files should show as clips in the event browser. You can click a particular clip and press the Spacebar to see the playback. Once you have selected that particular clip you want, it’s now time to add it to your Project Window.
iMovie users have differing opinions on how to add video. Some people prefer to do a first run edit the video while it is still in the Event Browser. That way all the editing is done in one swoop, whether you will be using that particular clip or not. This is usually for general settings like audio volume. On the other hand, other editors do not want to work with large video clips and prefer to select their videos, place it on the project file and then proceed to edit. There is no right way of doing things. Go with whatever makes you more comfortable.
Once you have determined the clip that you want to add, use the cursor to highlight the frames that you want. There are several ways to add the highlighted clip to the project. The traditional copy-paste shortcuts, COMMAND + C and COMMAND + V works. Click on the particular spot on the movie timeline before you paste. You can also click the Add Selected Video button. This will add the video at the very end of the project. You can then click and drag it to its correct spot on the timeline. Another method is to click, hold, and drag the highlighted frames onto the project are and drop it within any portion of the timeline sequence.