SFTP Method:
Tutorial Video. Step by step below;
1
First Step
Install an SFTP program(EX:WinSCP, FileZilla)
2
Second Step
Login to your Wepwawet Control Panel

3
Third Step
Select your Server

4
Fourth Step
Make sure to Turn OFF the Server

5
Fifth Step
Head to the Settings Tab
6
Sixth Step
Copy the Server Address and Username
7
Seventh Step
Open the SFTP program.Paste the Server Address into the Host box, The Username into the Username boxFor the Password box, Type the password you use to login into the Wepwawet Panel.Port will be automatically entered.Then click QUICKCONNECT
8
Eighth Step
Select all the three world files (world, world_the_nether and world_the_end) and Delete them
9
Nineth Step
Rename your custom world folder to world (capitalization matters)
10
Tenth Step
Upload the world file from your Local Storage to the Server.
11
Eleventh Step
Head over to your Wepwawet Panel and Start the server.
There you go! Now you know how to upload your own Custom World!