Once you have trained your dog to sit, you can then move-on to teaching him to stay.
Stand in front of your dog and command him to sit.
Once he has sat, command him to stay. You can raise your hand as a signal to stop and hold it out in front of your dog.
Then slowly move away a step or two.
If your dog stays there for a couple of seconds, return to him and give him a treat as a reward. Make sure that he stays in the sitting position as you reward him and does not stand or jump up. This will ensure that he does not think he is getting rewarded for getting up. This will facilitate in teaching your dog how to stay.
Do the same thing again, but move further away this time, and increase the time that you make him stay by a few more seconds. Keep doing this until your dog can stay put for at least one minute. Make sure that you reward him the whole time and give him plenty of praise if he does what you want. This will train your dog to stay.
If at any stage he starts to move or get up, go back to commanding him to sit. Do not give him any treats until he performs what you have asked of him. It is important to keep eye contact with your dog while you are stepping away from him to avoid losing his attention, as dogs have only a short attention span.
When you see that your dog is becoming bored or losing interest in the training, stop and give your dog a break. You can try again, at a later stage. You can also place food in front of your dog, make him sit and stay and then say the word “OK” when you want your dog to retrieve the food from the floor.
Hopefully you will manage this exercise and teach your dog to stay.