How To Install Mohist
To get plugins to work on 1.12.2 Forge you can use Mohist.
You can download this via our version installer, just select Mohist from the drop-down.
Head to this link: https://mohistmc.com/download (opens in a new tab)
Here download the latest version for 1.12.2 and upload it to your server via the file manager
Set the Mohist jar on the overview page, and you're all set.
You can now add plugins to the plugins folder in the file manager.