Steps
Getting your local save file
Your save file is hidden away on your computer, you will be able to find it in this location: *C:\Users{username}\AppData\LocalLow\Endnight\SonsOfTheForest\Saves*

Open the folder with all the digits, e.g. 76561197967057037
Open 'Singleplayer' or 'Multiplayer'
Open the most recent save (or the one you know you want to upload)

Zip the files or transfer the files via FTP. Our FTP Guide can be found here
The files need to be placed in userData/Saves/DedicatedServer/Multiplayer/0000000001
- If you're not using slot 1 you will need to pick the folder relevant to the slot
Restart your server
