Choose a place in your yard like the wall of an outdoor structure, fence, or gazebo to attach your trellis. Existing rose gardens can be trained to climb up trellises when it is positioned in back of them. Make sure that the wall does not cast too much shade for the roses to grow. Roses need at least 6 hours of sun a day.
Attach spacers to your trellis, so that the roses get enough air circulation. Trellises attached directly to walls will not provide enough air, which can lead to roses spreading diseases. Follow the link in resources to get instructions on how to include spacers. Mount hooks to fences when attaching to a fence. You can also extend the height of a fence with a trellis.
Prune any damaged or diseased canes from your rose bushes. Start your climbing roses off on the right foot by using only healthy rose canes.
Dig a hole two feet from the trellis that is twice the diameter and slightly deeper than the rose's root ball. Place your rose plant in the hole and tightly pack the soil to prevent air pockets. Make sure that the graft is slightly above the ground when planting in warm climates and two inches below the ground in cooler weather temperatures. Spread mulch around the base of the plants to lock in moisture. Water thoroughly.
Place your rose plants next to the trellis. Tie with strings to the rose's main canes to the trellis. Rose bushes have one main cane and many smaller canes growing from the main one. You can train them to spread in different directions as long as they are horizontally.
Allow your plants to become established for two growing seasons. Prune off any tangled or awkwardly growing canes.