Dog class trainer teaching dogs to 'sit'

The video tutorial discusses the importance of attention span in dog training, emphasizing that it takes repetition for dogs to understand hand signals. The instructor demonstrates using food and a clicker to train puppies, highlighting the role of concentration. The tutorial explains the meaning of hand signals and encourages practice to improve the dogs' response time, noting that with understanding, dogs perform tasks more quickly.

Describe the process of using a clicker in dog training as mentioned in the text.

What should a trainer do when the dog starts to understand the hand signal?