I was just wondering how I find the section where I can extend my vocal range as I really want to sing higher because whenever I sing higher I am quiet otherwise I strain if I try and go louder.

Hi Mads,

You may want to work on mastering your vocal and pitch. Here's a great lesson on pitch here: https://www.30daysinger.com/tutorial/key-to-perfect-pitch-and-intonation/1

If you have not yet tried the 30 Day Beginner, course I recommend doing so. In that course, the instructors will touch upon how to practice higher-pitched singing and do so correctly so you are not straining your voice. 

Choose one of the beginner courses here: https://www.30daysinger.com/beginner