Putting a custom modpack on your server is very easy and can be done by following steps below:
1. Stop your server and remove any old files you might have on it.
2. Download the modpack files of the modpack you want to your computer, and get them ready:
Generally, modpack files come like this after you unzip them:
1: This is the main server jar. It can be named something like that, or forge-something, or with the modpack name. You will need to rename this file to custom.jar
2 & 4: These .bat and .sh files are used to launch the server when running it yourself, and not with a host. They can be deleted. There is an exception for some modpacks if you see a file called FTBInstall.sh and FTBInstall.bat. See below.
3: Usually there will be a file called minecraft_server.XXXX.jar you want to leave this file alone.
After you rename the main server .jar file and delete any files that are not needed you should end up with something like this:
Modpacks containing FTBInstall.sh and FTBInstall.bat files:
If you see FTBInstall.sh or FTBInstall.bat files you will need to execute one of them. .bat is for Windows, and .sh is for Macs and Linux.
After running one of the two FTBInstall files you will see that another file appeared:
Now you can rename the main server .jar (FTBServer-1.7.10-1408.jar in this case) to custom.jar and delete the .bat and .sh files as they are no longer needed, so you end up with something like this:
Please also note that if you are loading a modpack that required Java 7, instead of Java 8 you will need to rename the main server jar to customjava7.jar instead of custom.jar. This will load the modpack using Java 7. Any modpack that is under 1.7.10 (1.6.4, 1.5.2, etc) and older 1.7.10 modpack will all need to be loaded with Java 7.
3. Upload your custom modpack files to your server using an FTP client. You can find a tutorial on how to setup an FTP client to manage your files here.
4. In the Multicraft panel using the JAR Selection Menu select Special: custom.jar and click the Save button. This will tell your server to load the custom.jar file .jar you had renamed in the previous steps.
5. Start your server
If you get stuck we can get the modpack on your server for you:
Premium servers - If you have a premium server you can just create a support ticket and we can install it for you as long as you can provide a place where we can download server files for the modpack you want.
Budget servers - Modpack installations are not included with Budget servers, but you can purchase a one-time installation service here. If you already have the premium support addon on your Budget server you can just create a support ticket, no need to purchase the one-time installation as premium support addon includes modpack installations for Budget servers.
If any information you see here is outdated please let us know by creating a support ticket. Thank you.