To install Forge please watch the youtube tutorial below:
To install your own custom version of forge, please follow these steps:
1. Download the “installer” for the version you want, from here: http://files.minecraftforge.net/
2. Once it has downloaded, run the “minecraftforge-installer-xxxx.jar” file.
3. Select “Install Server” and pick an appropriate directory on your computer for it to download, you will need to retrieve the files later on.
4. Once the files are downloaded, check you have the following files & folder:
minecraft_server.xxxx.jar
minecraftforge-universal-xxxx.jar
library (folder)
5. With these files & folder, you now want to upload them to your “jar” directory of your server. For information about uploading files via FTP, see the tutorial here: https://clients.minecraftserver.com.au/knowledgebase.php?action=displayarticle&catid=1&id=1
6. Once all the files are uploaded, go into Multicraft, and add the full name of the “minecraftforge-universal-xxxx.jar” to the “Server JAR” area.
7. Press “Save”, then restart the server.
(Ensure that when you install forge, you don’t have any modpacks installed on the server, it needs to be mod free, install the mods after you have Forge Modloader correctly working).