Not knowing which slides you’re referencing directly, I think that the difference from push to pull is on the Event Handling side, were as the JGroups/SpringCloud things you reference are specific modules only used when you’re distributing the command handling side of your application.
Additionally, it wasn’t a requirement in Axon 2 to run an Axon app clustered and that’s still the case; that’s up to you if you want that.
If you just use the defaults as provided through the ‘axon-spring-boot-starter’ module, you get a Axon 3 based app with sensible defaults for all the important components.
That should give you an application were you can just use the basic command, event and query components.
Hope this helps!