STEP 1: LURE THE DOG INTO SIT
Stay in front of the dog and lure him into sit position by going with the treats above and towards him from his nose. The moment his butt touches the ground click and treat him.
STEP 2: ENCOURAGE HIM TO STAY
Once you get him to sit keep rewarding and clicking him for as long as he stays sitting. At first keep treating him every second and then gradually increase the time duration between treats.
STEP 3: RELEASE CUE
Tell him or show him a mark for release as shown in the video, and encourage him to stand. The moment he stands, click and treat him.