The primary modes of funding available to students are Graduate Research Assistantship (GRA) positions and Graduate Teaching Assistantship (GTA) positions. Both opportunities are based upon student and faculty interaction.
At this time you have been admitted without funding, however now is the time to contact faculty and express your fit and interest in their group.
Faculty offer GRA’s based upon the projects they plan to have available in their group in the new academic year. Faculty can also nominate students for GTA consideration if they believe there is a research fit but still working out more long-term funding options for students with whom they have an interest in working. Your first goal should be seeking out a potential faculty advisor based upon fit (research interests, personality, lab structure, etc.). If you contact faculty and find the right fit, your chances for funding go up exponentially. Faculty may contact you between now and April 15th to discuss opportunities, but you should be proactive for the best chance of receiving support.