Full tutorial on how to set Alias email?

Current alias mail tutorial is too hard to read, is there any better detailed ones like in a youtube video or article etc?
I want to make email alias for hewan.org
but I am not too sure what the host name and server things are or how to do it etc?
I am trying to use mozilla thunderbird but it just doesnt make sense to me

[alemoppo]

I want to make email alias for hewan.org

For the second level domain, you have to use an external services, like zoho.

Bye!