If you want to cut out this or that part of the video from the initial one, you need to work with "Video Editor". The process of editing is performed by means of timeline.
To delete some fragments, you have to choose this episode with the help of timeline and press the button "Add area of Deleting" or just push "Del" on your keyboard. The deleted part will be added to the list of "Deleted areas", and shown on the timeline. If you want to cancel the process of deleting, you need to point this part in the list of "Deleted areas" and then press the button "Remove Area of Deleting".
To cancel all the created changes, please, push "Remove All Areas of Deleting".
It is necessary to mention, that all the changes can be used only to the result video (the initial video will be without any alteration). In order to make all these changes, you just need to convert the file into one of the formats, chosen by you, and only after that, all the alterations will be really performed.