Measure and cut pressure-treated 2-by-4s for the deck skirt framing. Measure from the center of one deck post to the center of the next post.
Attach the measured 2-by-4s to the center of each deck post across the top of the space to be enclosed. Use 3 1/2-inch screws and a handheld drill to attach the wood to each deck post.
Mount the pre-measured 2-by-4s to each deck post across the bottom of the enclosure space, again with 3 1/2-inch screws. Make sure the bottom 2-by-4 is just above the ground and not digging into the soil. Contact with the soil will cause the wood to rot over time.
Measure and cut the lattice material. Use reference points to measure the lattice, such as the top and bottom leftmost corners of the frame boards. Make sure the lattice is aligned in a straight line between the top and bottom frame boards at the reference points. Holding the lattice in place, line up the lattice material with the frame boards and mark the lattice at the first obvious corner. Cut the lattice in a straight line at the mark. Repeat for each lattice cut so that you have a measured piece of lattice for each side of the deck.
Attach the cut lattice to the top and bottom of the framework with 1-inch screws or finishing nails. Start at one side of the enclosure space and work around the deck to attach the lattice to the framework until the space is fully enclosed.