Turn the filter on. Open the skimmer top and set it aside in a safe place so it doesn't fall and crack.
Remove the skimmer basket and set it aside as well. Connect the telescopic pole to the vacuum head.
Connect one end of the pool hose to the vacuum head. Drop the vacuum into the pool. Take the other end of the hose and secure it to the vacuum attachment piece that came with your skimmer.
Place the end of the pool hose with the skimmer attachment near the pool's return jet to allow the hose to fill up with water. You may find this easier to do without the vacuum attachment connected. If so, disconnect the attachment and replace it immediately after the hose fills up with water.
Drop the hose immediately into the bottom of the skimmer. The attachment should rest securely on the bottom of the skimmer. Wait a few minutes for pressure to build inside the filter. Once the return jet starts flushing the water with regular force, the vacuum is ready to use.