How to create a Structure file realm works

[Sir.Nel]

I have made a realm On Realms Works way back about six years ago. I can make a copy of the realm but cannot export the structure or full\partial contents of my realm. I also Created a brand-new realm to import the files, but there's is always an error. I don't know what do I follow the video tutorial https://www.youtube.com/watch?v=QPVFCSsq1oI&t=12s step-by-step and I still don't know what I'm doing. Just to let you guys know the video does not tell me how to Create the structure file, it's just on the export part.