You can add an image grid either on the 'Quick Edit' screen or the 'Advanced Editing' screen.
Here are the steps to add an image grid to your scene:
Step 1: Go to the scene where you want to add the image grid.
Step 2: Go to the 'Elements' tab and then to the 'Layouts' section.
Step 3: Select the number of images you want to have on your scene.
Step 4: Select from the different animation options available.
Step 5: Individually replace dummy images in each part with new ones from the 'Media' tab.
Here is a short video to take you through the process: