You will need:
Ribbon, Leotard, ballet basque or dance briefs
Snaps (only if using Ribbon)
Stiff petticoat tulle
The tutu should be attached to dance briefs. The tutu could also be attached to a leotard for a beginner, but they are typically worn on dance briefs (or a basque) either with a bodice, or attatched to a bodice.