Simple open your Plugins page on your WordPress Admin Page, and search for "mxPress" and click on install.
Then click on 'activate'.
Go to the 'Appearance / Mxit Settings' page, and configure either your Front-Page or Home Page, depending on whether you have your WordPress theme configured to show a static frontpage or the default homepage.
We recommended you create a new Menu in the WordPress Menu Manager called "Mxit Menu" with the pages and categories you want to show in Mxit, and then go to 'Appearance / Mxit Settings' to configure mxPress to show that Menu.
What happens after I have installed the plugin?
Go to the Mxit Developer Site (http://dev.mxit.com) and register your Mxit App.