Keys management is not going to be easy unless one trusts someone to manage keys for them. Recently, I believe that the most user-friendly way to create a new account is via https://hiveonboard.com

There is some basic information about the keys there. Also you can check a few posts such as @hivepeople/zpkknkag and @stellabelle/get-your-free-hive-account

It looks like a straightforward way to create a new account unless you want to create one with your own RC. Other account creation providers are listed at https://signup.hive.io. Those pages may give your students some overview until you can come up with your materials.