Problem installing guest additions on the virtualbox

Hello everybody! I’m excited to start this journey in the Odin Project.
I was hoping somebody could help me with a small problem I ran into today.
So after installing xubuntu on Virtualbox,I tried to install and enable guest additions as per the specifications on Step 3 in the Prerequisites Lesson in the Web Development 101 chapter. After I opened the terminal I typed in “sudo apt-get install build-essential”, and " sudo apt install linux-headers-$(uname -r) build-essential dkms ."after that.
However I came up with the errors seen in the Terminal4 file. Could somebody be so kind to explain to me where I went wrong?
Thank you so much!

Solved it! Instead of the code that Odin project told me to run, I ran sudo ./ and then I continued with the instructions.