Here are a few plugins used in Multimedia Desiger classes, and on my website Multimusen.dk

Hierarchical taxonomies for WordPress. Probably you'll adapt it to your site, and add a more suitable headline than taxonomies. For instance music genres, languages etc.

Case: For instance my website Multimusen.dk has posts in Danish and English. I use taxonomies in order to separate Danish and English content.

For more information see

Experimental: editor in the dashboard for certain post types. For more information and tweaks see WP Developer's Handbook and register_post_types

1. Zip the directory with the plugin you need.

2. Plugins > New

3. Select upload
4. Choose your zip file

Copy the directory with the plugin you want to:

yourWordPress/wp-content/plugins

Here you can use whatever ftp client you fancy, e.g. Filezilla, Cyberduck, ftp from the bash prompt etc.