Create a plugin

No

There is a way on having your own plugin I havent tested it yet tho

1st.is go to Files

2nd. is go to Plugins

3rd.is go to the folder on the right tab

that folder + sighn right there

4th is name it what ur plugins name is

5th is open that folder and start coding the plugin of yours

and once ur done coding test ur plugin!

That's not how it works. You are just creating a text file, not a plugin file, and no, you can't add custom plugins or upload plugins. Read https://support.aternos.org/hc…ding-files-and-FTP-access

Ok I just thought that would work

If you create a plugin you can upload it to http://dev.bukkit.org/bukkit-plugins/ , https://www.spigotmc.org/resources/ or poggit.pmmp.io and request it on Aternos (if it has at least 1000 downloads)