Can't upload demo data

Hello Blue owl

I had contact with my hosting provider but they wont increes the limedes.
so now i have to do it with the fille zilla ( never used it before)

I can log in to the ftp of my website but where do i need to upload the demo data?
i have read something to host it local en than duplicated it but i dont know to have a local wp.

So can you please help me out?

Sorry for my bad english btw

Best regards,

Nick Severijnse