Well nowadays maven is really an essential thing to have under your belt so I would suggest with starting with their getting started documentation. Really everything you need to know is freely available on their website. They even have a free copy of the Maven 2 Oreilly book available for viewing last I knew.
I would start here for familiarizing yourself with maven.
http://maven.apache.org/users/index.html
Now as for setting up your hello world project when you use the template project it puts all your dependencies and such in the POM file for you. If you are unfamiliar with POM files please see the above link.
In STS go to File -> new -> other -> maven -> maven project and click next
When you get the the archetype selection if you are doing a web app then choose maven-archetype-webapp otherwise for a stand alone application the default quickstart that is highlighted is fine.
STS will create the project structure for you. Next I would suggest (after reading the documentation provided in the above link) comparing the POM file generated when you create a spring template project to that of the empty one generated when you created a new maven project. You can mostly just focus on the items contained in the <dependencies> tags. These are the libraries that will be pulled into your classpath that are needed on your projecct build path. For a hello world application you will probably not need all of them start with the basic ones and add what you need if a class is not found.
This blog post is a little dated but is applicable.
http://blog.springsource.org/2009/12/02/obtaining-spring-3-artifacts-with-maven/