General advice needed

I want to set up a ‘gateway’ page that allows users to choose one of my sub-sites.

For example:
allmystuff.com would take users to a page containing links, buttons or images that when clicked lead to my various creative endeavors.

Allmystuff.com
— Books
— Songs
— Poems

Each of the subs being sufficiently separate that I can make changes to one that don’t affect the others.

* How would I set up something like that?
* Do each of the sub-sites require a separate installation of WordPress?
* Do each of the sub-sites need separate domain names?

Thanks – rev