Gather supplies and plug in hot glue gun, if desired.
Arrange floral stems into desired shape. Play around with the stems until you are happy with the shape and size.
If you use two stems to create one longer stem, use as little tape as possible to adhere them. Floral tape is removeable and easy to work with, so don't worry about making a mistake.
Once you have a shape you like, cut any stems as needed. I recommend cutting excess stems after you have your final shape, just to make sure you're happy with it first.
Adhere stems together with floral tape. Note that you will need to go in every direction several times. Press to seal tape as you do so. Optional: You may use a touch of hot glue as well.
If you want to secure any stems together for a tighter look, you can do so with a small piece of floral wire. It is thinner and less visible than tape. Or you can choose to leave the ends of your wreath loose for a more natural look.
Notes
For curved letters, choose wired floral stems that will better hold the shape.