Trouble installing plugins

Hi. I’m having trouble installing plugins. The calendar plug-in words, but hello-world, and emoji-picker do not. When I turn on hello-world, the “hello world” window does not appear. When I install emoji-picker I get no option to use the plugin in when using the slash command. I have ensured that my version of node.js is up-to-date, so this can’t be the issue. Any tips?