Î forgot to mention 1 thing. In the video you can see this "fx" beside each "mp4" file. The fx stands for effects applied to that mp4 footage, clicking once on that fx will deactivate it and turn off every effect applied on that footage. If you are working on something and focus on something specific where the effect is not needed and you just wanna preview through that point, disable it. To enable it just simply click on it again.