
At 20 weeks he is still a very , very young puppy and hasn't learnt how to behave fully yet.
Keep up the toilet training ....much praise when he performs outside (you should be taking him out and not putting him out) just clean up any accidents quietly
When he jumps up at you , cross your arms and turn away ..make no eye contact ..completely ignore him until he sits quietly for a few minutes..it will take time but he WILL do it. When he sits quietly , then fuss him up. Make sure the whole family does this as well as any visitors to the house
Make sure all bins and bin bags are out of his reach. Get a kiddie gate and make sure he is behind it when the children eat their meals so he can't jump up and get their food.
Keep going to the training classes ..he will be learning and food bribes are an ideal way of training him
Buy a copy of The Perfect Puppy and read it
You have a puppy , he can no more act like and adult dog than your youngest child can act like an adult person yet
Melody