One way: "Cut" the scenes that you want to remove so that they're separated from the remaining video, then delete those scenes.
Scrub to start of scene to remove, click the razor icon.
Scrub to end of scene to remove, click the razor icon.
Click on the scene you wish to remove to select it.
Click the "trash can" icon to delete that scene.
Lather, rinse, repeat until done.
BittMann