You need to take a screen shot within the Create a Highlight mode. First play a match and at the end when the menu appears with EXIT, REMATCH etc, select the Highlights option.
In this option select 1 of your highlights and save it!
Next return to the main menu and go into Creations and select Create a Highight Reel then choose NEW.
You now have to select ADD VIDEO CLIP and choose your saved highlight. when this is done all of the other Edit options will be available to you. now move down to the SCREENSHOT tab represented by a camera icon (bottom row second from the left). Once selected just use this option to take and save a picture from video clip. you can take the very first second or role through the video for any moment you desire. Either way when you select it and take the still and save it for your Achievement to unlock.