WordPress is the most used hence the most targeted CMS.
Installing WordPress is just the easy part, after that you must configure your CMS to get every thing working correctly.
It is important that your web site display its pages quickly for your readers but also for the search engine that gives poor notation to slow web sites.
You want to add a slider to your WordPress web site ? Follow the guide !
A few pointers to create a theme for PluXml in particular and any web site in general.