Stems from cut rose blooms are very unlikely to root successfully. However, I’ll give you a simple, effective way to root roses in case you have access to some bushes you wish to propagate.
Take 5-inch long cuttings from new stem growth (not bloom shoots) in the zone where the stem begins to change from succulent to woody. Cut toilet paper tubes in half and fill with a fresh rooting or potting mix. Wet the mix and allow to drain. Remove the bottom two sets of leaves from cuttings and dip in commercial rooting powder (like Hormodin or Rootone).
Use a pencil to make a hole in the rooting media and insert the cutting. Firm media around the cutting and place three or four in a quart ziplock bag. Seal the bag two-thirds of the way and hang or set in a bright, cool location out of direct sun. Check weekly after 3 weeks for roots in the bottom of the toilet paper planting tubes. You can usually transplant to a pot after 4 to 6 weeks.