1. Upload the plugin per (S)FTP or Network Admin/Plugins/Add New/Upload.
  2. Deactivate the Free version if you want to install the Pro version. Do not uninstall, just deactivate.
  3. Activate it as network plugin in  Network Admin/Plugins/Installed Plugins. Click Network Activate here.
  4. Go to Network Admin/Settings/Multilingual Press now, and activate the features you need.
    • If your theme supports widgets, deactivate the feature Quicklink.
    • If you activate the Custom Post Type Translator and your post types don’t show up, make sure they are registered in a network activated plugin, or at least on the main site. If your custom post types do show up, you can enable dynamic permalinks if Multilingual Press cannot find the correct pretty permalinks.
  5. Now go to the Language Manager menu entry right below the Multilingual Press section. Find the languages you want to use, and set their priority to higher values. The original language should always be set to 10, the translations to a slightly lower value, depending on their quality. This affects the order of the language selectors and the HTTP redirect feature. See Language negotiation – how our redirect feature works.
  6. Head over to the Network Admin/Sites configuration. On each site, go to Edit/Multilingual Press, and choose a language and the relationships.
  7. You can set a preferred language for admin pages in your profile to get the same language on all sub-sites, if you have installed the translation files for that from WordPress.
  8. Now switch to the dashboard of a site, and go to Appearance/Widgets. There is a new widget now, named Language Switcher. Add it to a sidebar.

That’s all. You are ready to write your translations!