Position a ladder next to your gazebo. Climb to where you can reach the roof of the gazebo.
Untie the string connected to the canopy from the gazebo frame. Set the old canopy aside.
Open and lay the new canopy on top of the roof. Tie the strings around the frame to secure it.
Get down off the ladder and step inside of the gazebo. Loosen and remove the strings or rings holding the netting to the frame. Set the old netting aside.
Open the replacement netting. Holding the top of the net, position it at the frame level. Tie or secure the rings to the frame. Work around the frame until all the netting is installed.