The Homepage is not enabled by default for all users. This page explains how to enable by checking two checkboxes in your preferences.
The following explanation would cover the cases where you are a wiki instructor and want your mentees to have homepage enabled, or if you want to try the homepage for yourself.
Newcomers who have Homepage enabled by default have both checkboxes checked.
To check if your Homepage is enabled, just type
Special:Homepage in the wiki's search engine.
Enable the Homepage
To enable the Homepage, go to your user preferences, in the User profile tab.
There, check on the "Newcomer editor features" section, for the "Display newcomer homepage" checkbox. Check this to enable the homepage.
Enabling the Homepage adds a new tab close to the user page and user talk page tabs. This new tab is labelled "Homepage".
Make the Homepage as default
Enabling the Homepage shows another checkbox in Preferences, called "Default to newcomer homepage from username link in personal tools". Checking this checkbox will make your username in top right go directly to Special:Homepage rather than to your user page.
The target of your username will not change for anyone else than you, and it will not take effect anywhere else.
Enable the help panel
If you want to work on Suggested Edits provided by the Homepage, then you must enable the Help panel as well.