Short regular Ob. Marlee, I have been training since she was 9 weeks old. Just a busrt of training here and there. To help pup walk on the leash use lots of encouragment, start using a command you want to use in the future, ie Heel or close....then when you go on short walks or around the home use your command in a happy chirpy voice, keep them focused and he/she will not even realise they are on the leash
Example.
"Close, what a good girl/boy, Close what a good doggie woggie"
If your voice isn't enough get a squeaky toy to hlp keep him/her focused, hold the ball with the opposite hand to the side you want the dog to walk on, hold close to your shin the side the dog is on... so doggie isn't have to jump up to see what you got. When you have a successful walk let pups run free with ball for a bit

Dogs/pups like to end on a good note

Then put ball away for next lesson or walk
