Since Nvu 0.90 does not allow you to arbitrarily position text and graphics on your web page, nor does it allow you to create multiple columns using Cascading Style Sheets (...snip...) from the WYSIWYG interface, you will have to use an old webmaster trick to accomplish this.
The tutorial goes on to use tables for a multi-column layout, urgghhh. However, the truth is that Nvu has been quite capable of creating multi-column layouts using just its WYSIWYG interface i.e. just the GUI without any source-view editing.
So, to prove my claim about Nvu's capabilities I cooked up a page a few days ago which uses pure CSS for the multi-column layout. Nvu's in-build style sheet editor, CaScadeS, was used for the layout generation. At no point during the creation the of the demo was it required to edit from source-view. I know Nvu's style sheet editor has its short comings in user-friendliness, and unimplemented CSS2.1 rules, but still it is feasible to create multiple column layouts with Nvu.
The demo features on Nvu's demo repository.