How long does it take to edit the videos together?

It usually takes me about 2 days in all.  I start by converting the footage from the GoPro files to something easier to edit with.  I then synchronise the various camera angles and sound, then start a rough cut.  This involves working out what the ‘story’ will be, and being brutal about what to cut out.  A fine edit follows, with a script if required, then a sound mix, then graphics, then a colour grade.