if I type in /plugins, nothing shows up
does your server not run or does the commands just not work when you are on it.
Firstly, when you type commands does nothing happen or does it say Unknown Command? If it says Unknown Command, that means it's broken, if it says nothing, go to your server console and look for the part where you issued the command. If it was executed normally (according to the console) that means the plugin is broken and you need Aternos to fix it. If it says there was a problem that means there is a chance that you might be able to fix it without going all the way to fix it.
If there was a problem in your console post the error message and see if anyone else can help you (cuz i'm not very good with plugins/modpacks)
Hope it was helpful