Floral adhesive is needed to glue the individual tulle puffs in place. This type of adhesive holds even in wet foam. Hot glue or cold melt glue doesn't hold as well and tends to pop off if the final bouquet is refrigerated.
Dip the twisted wire stem of the tulle puff down into the neck of the tube of floral adhesive, coating it well as shown.
Insert into the foam right above the caged edge of the bouquet holder.
The puff should be fluffed out and create a circle pattern around the perimeter of the Oasis foam head.
Continue gluing all the tulle puffs in the foam, keeping them placed tightly together.
The collar really takes shape pretty quickly.
Keep it tight so the puffs will flare out. The collar is designed to be one of the major elements, so you won't want to cover it up with flowers. Rather, you want to frame it.