How To Make Server Files
If the modpack you're looking to play on your server doesn't have server files, or if you're making your own custom modpack, here is how you can get it running on your server.
Installing Forge or Fabric
First you need to install Forge of Fabric on your server. Making sure the same version is install that your modpack is using. If using the Curse Launcher you can see the mod loader version when press on the details of the modpack.
You can find guides of how to install Forge and Fabric by using the menu to the left, or the search.
Upload Your Mods
Now we need to upload the mods to the server. To do this make a folder called mods in the file manager.
Then ZIP the mods from the client and upload them to the server via the file manager. You can then right-click and press unarchive to unzip them.
If you're not sure where to find you mods. If using the Curse launcher, press on the modpack, then the three dots next to start. Here press open folder. Your mods will in the mods folder.
All the mods should now be uploaded in the mods folder on the server.
Removing Client Mods
Some mods will only work on the client, and therefore will crash a server if uploaded. Depending on the version of Forge/Fabric you're using or the mods you're running, these mods might be ignored. However, in most cases there will be a server crash.
To fix this, you need to delete the mods from the server.
On the mod menu in your game, you should see what mods are for the client and what are not.
You can also read the server crash report.
Start the server, let it crash, then head to the file manager, then the crash reports folder. In here it should point to the mod causing it. You might need to do this a few times.
You should now be all setup with your modpack.