Camera modes

Hi so may seem a silly question but my daughter really wants to make YouTube videos with the help of me and my wife but we are both completely new to any kind of video filming although I am a half decent editor but I'm having serious issues with camera focus eveytime there's any movement from my daughter she looks completely blurred I'm currently using the video mode on my mirror less camera I have no idea what the other modes are or do they are SMART P A S M and SCN can anyone tell me what these mean and which would work best for video as the quilty looks fantastic but this issue ruins the shots. Thanks guys.