To sign later, take your dominant hand and start with an 'L'-sign, with your index finger and thumb extend at right angles. Take your non-dominant hand and hold it up flat, facing your 'L' hand, with your 'L' hand's thumb sticking to the palm of your other hand. Hold your non-dominant, open flat hand steady as you pivot your 'L' hand 90 degrees, over and down.
Teaching patience is an important skill for young children. Using the later sign lets your baby know that you have heard the request and will attend to it, but they need to wait.
Teaching your baby to learn to wait for something is an important developmental skill. When your child makes a request, use the later sign to let them know you have heard them, but they need to wait for a few minutes before you will attend to them.