Floating Flower Tip - Most flowers float pretty well on their own until they start to pool with water and slowly sink. For a longer lasting centerpiece, use bubble wrap to make little skirts for your flowers.
Glittery glue dots - for magnets! It looks like those glass filler stones (or maybe dried resin or glue? hmmm), and glitter for the materials - No instructions, but it seems pretty simple going from the pictures.