
For Forge modpacks, there are two jars, a Forge universal jar and the Minecraft jar.

MINECRAFT SERVER FILES INSTALL
If you run it locally, make sure you install the server jars and libraries alongside the installer jar/script. You can either run this locally (ie before uploading to AMP), or on your server once the modpack is uploaded and extracted. In other cases, you have to run an installer jar directly, or an install script (eg called Install.bat for Windows or Install.sh for Linux) that runs an installer jar, to download the required server jars and libraries.In that case, you don’t need to make any changes to the modpack and can just upload it as outlined in the recommended method above. Some modpacks already include the required server jars and libraries.Otherwise when you extract the zip in AMP it will be installed in a subdirectory of the Minecraft directory, and won’t work. Make sure that the zipped modpack that you are uploading to AMP is not a zip of a directory containing the modpack files and directories, but rather a direct zip of those files and directories.However, depending on the modpack, some additional steps may be necessary. The recommended method above applies equally to adding server modpacks to AMP. You can symlink the Minecraft directory under the new instance’s datastore to your existing directory.
MINECRAFT SERVER FILES FULL
Make sure to check the ownership/permissions to allow the user AMP is running as to have full read/write access. In the new instance’s datastore, there will be a file called MinecraftModule.kvp containing the configuration data for that module, you can edit the ServerPath setting to point to the absolute path on-disk of your existing server.

Right click your server’s jar file and select the ‘Set as startup jar’ option.Note that this option is only available when using the instance’s File Manager, not the ADS File Manager. Right click the server.properties file and select the ‘Import Configuration’ option.

Alternatively, go to the datastore directory for that instance and extract it as the user that AMP is running as.
MINECRAFT SERVER FILES ARCHIVE
