Three sets of columns to 1 set...

Hello,
Can't think for the life of me how to do this. I've attached a sample input, with a spreadsheet with my desired output. Any ideas? I always try the unpivot columns, but I can never get the selection right...
Thank you in advance!

Nevermind. I've solved it. Don't know what I was doing wrong. I also included my solution for calculating time difference to the quarter hour, if anyone has any input on my steps or different methods, feel free to chime in. Thanks!