Vocal scales/Warm-ups

As a vocalist especially studying it academically it is important to be able to a good range to extend that range it takes time and practice. One of the ways to do this is to practice vocal scales my range is alto see diagram below. As a self-taught vocalist, I haven't actually practiced vocal scales a lot so I am quite new to vocal scales/warm-ups

When looking for vocal scales to practice I made sure it was in an alto range to make sure I could sing all the notes in the range comfortably before moving forward into more complicated techniques. 

https://www.youtube.com/watch?v=N8W17MXgvOQ Throughout the year this is the video I have used to help me warm up my vocal chords before performances and individual practices at home and as and when possible. Doing this warm up helps me keep in pitch and helps stopping my voice from cracking.