I want to sort of re-create homepage of wikipedia.org (with globe and links to language versions of wikipedia) for my project but would like to insert image of my choice instead of globe and with titles of links appropriate for my project. Is there some template for that or tutorial?
Topic on Project:Support desk
That page is not part of mediawiki. You can create it yourself like you would any other web page.
FYI, the code of the portals of wikimedia are managed in: https://github.com/wikimedia/portals