You can upload your world directly to your server via your Clanforge page. Once you have connected to your server's Clanforge page, you want to click on the World Management button shown below. 

This will provide you the following dashboard:

Backup my worlds - This option allows you to make a copy of any of your saved games that are currently on the server.

Reset my worlds - This option allows you to set the server save back to the default world in case you wish to start fresh.

Upload a world - This allows you to upload a .zip from your local computer to your servers backup folder. 

Restore a backup - This will list all saves that you currently have in your backups folder that can be restored into your server. 

Uploading the file:

To upload the world you will first want to select "Upload a world" 

From here it will ask you to specify the following:

Game - Factorio 

Mod - This will default to the current mod that you are running on your server. It will allow you to pick between Stable and Experimental builds.
Type of File - In this case you need to select World.

Server - This option allows you to specify which server you want to upload to, if you only have one it will default to your current service. 

Description - A brief summery of what the file is e.g. Fresh World 

Instruction - As this is an automated process you won't need to write anything in this text box.

Upload a File - This is the world file you wish to use. IT MUST BE NAMED "" 

Once all these fields are done you will see the "Upload" button turn green meaning it is ready to upload. 

When this is completed uploading, you will be able to find the uploaded save under "Restore a backup"

Congratulations you've just completed your save upload.
If you ever have any issues please contact our support team who will be happy to assist you!