get user_page and modify main content
I get the impression you want to create pages out of components, so rather look at Panels (and Panels Ajax Tabs). 

In order to use panels properly you have to learn how to use Page manager also as Panels integrates with it. The best online tutorials on that subject are from Johan Falk at Node One, Learn Page Manager! series. Tutorial 4 - 7 of that series deals specifically with Panels, but start at the beginning and work your way through it. You will also learn a lot about context which is an essential concept to master as a Drupal site builder.