Start with sit and stay. I start with the length of the leash. When you give the come command give a gentle tug on the leash. Then use a rope for a leash and get the pup to sit and stay up to about 15 feet. Once the pup can do that, come will…...come. Once the pup is off leash, still use the sit and stay method but get further and further. Eventually, the pup will know that come means to come. I would also use treats when the pup does well.