To group clips together:
Go to the Manage Timeline tab.
Click on the first frame you wish to group, hold down the shift key, and then click on the last frame you wish to group into the clip.
Click the icon with the pictures and an arrow that is going toward the film strip to group your selected images together.
To ungroup the clip back into individual frames, click on the icon below the one described above (the one with the arrow pointing at the pictures)