Here are the instructions from DIY Life:
(3) Faux flowers of your choice
(1) Wooden box (I re-purposed an old CD box I had on hand)
(1) Row of faux wheat grass (onion grass works well also!)
(1) Set of floral foam bricks
(1) Wood soldering tool (there’s a great, affordable option for beginners at Michael’s)
2. Arrange faux wheatgrass to cover every inch of the floral foam. At this point, you can also slide decorative paper into the side of the box to avoid any floral foam from peeking out.
3. Cut your faux floral stems to desired size (I kept mine a bit longer, but feel free to shorten the height so you can see over your centerpiece!) and arrange accordingly. The floral foam should keep them snug in place.
4. If you’d like, use your wood soldering tool to carve your and your Valentine’s initials in the side of your box — a sweetly personalized touch! I drew our initials in pencil first and traced them with the tool.
5. Presto, you’re finished!