Downloading the world from my server just gives me the default world that doesn't include everything I've built.

Me and my friends are trying to change the server software to Forge so we can use mods on our world, but it says I have to reinstall the server and that we will lose our world. So I downloaded the world from the server, and it gave me the world, but it was the original seed world which didn't have everything we built. Before I made the server I created the world on my computer, then uploaded it to aternos. Help is appreciated.

Nevermind, I downloaded it again and it included everything.