If you want to edit on your own device, you have several options of free editing software. Keep in mind that when you are using software like Kaltura for screencast or webcam recordings, you can edit directly in these programmes.
For Apple devices iMovie is a powerful video-editing programme that can be used on a Mac, iPhone and iPad. For instructions please consult the user guide provided by Apple.
You could also use Adobe Premiere Pro or the simpler consumer version Adobe Premiere Elements. However, you might need a licence if you do not already have one on your computer. Look here for a beginners’ user guide of Adobe Premiere Pro .