How the hell do I Shell this?

https://preview.redd.it/33npr1z77nbe1.jpg?width=1280&format=pjpg&auto=webp&s=5763bfe13239b4d46d0ce380abd88d9a35e752ac

https://preview.redd.it/aw3ac1z77nbe1.jpg?width=913&format=pjpg&auto=webp&s=99f238e09d032f4831bd2e1968046ecde21c3f3a

Do you have and advice or a technique or a link to a lesson that you can point me at?
I have been trying to shell this part like the original but I can't really seem to do it.
the shell command obviously didn't work.
I tried to do it with sketches and lofting but to no avail.
What should I do?