Help ..wild puppy

Hello

Hoping for some advice. I adopted a just 5 month old puppy.He is a pointer mix we think. We got him at the shelter. He was very skinny ( just treated for tapeworms) and he is little. Only 18.6 pounds probably about 5 pounds underweight. Bet believes he will be no more then 40.pounds so not sure of the mix. Looks very much like a pointer though. He is a scardy cat and is very sweet at times. It has been a week and each day seems to be the same. He is very housebroken but has no manners which is a bit odd. He will sleep.curled up on my arm all night from midnight till 7 am. He will take naps cireled up with me like a sweet baby. But when he is awake oh my goodness. I have dogs my whole life and puppies. I have had misbehaved puppies but never one that doesnt understand no. I have a 14 year old dog ( her sister passed 2 months ago and they were together her entire life) I expected problems from her because she isnt super dog friendly but was lonely. She has very much accepted him and a little more pep in her step. I will.list the issues below. I am walking him a few times a day and he goes on a car ride each day to see the horses and to walk in the woods. So he gets out.

1. Crate did not go well. He will bark and bark and bark in the crate. I live in an apartment so I had to give in or we get kicked out. I ordered a no bark collar for small dogs. It just has vibrate and beep no shock at all. That should be here soon.

If I could out him in his crate when he is bad that might help but he barks and whines and tares at it.

2. My senior dog accepted him but he pushes it and I am afraid he will get her to not accept him. He has crazy wild spurts throughout the day. Tons of zoomies and then he will run crazy circles around her and bark. Then he will not let us catch him to stop him just barks and runs like a full and continues crazy bigger circles. When we do catch him we have tried numerous things. First a rolled up newspaper smack ...does nothing he just tries to grab the newspaper and chew it up. Then a hand smack ( I hate) and he is boney so it is more for the effect then a hard smack. He doesn't care. Yell no..he doesnt care hold him tell him no he just goes wild to squirm away and continue what he was was doing. If we try to hold him still he will bite. Not a nasty mean dog bite but biting so we let go I smack his nose ..doesnt phase him at all...smack I tried.a flick to his nose lol.doesnt do a thing he just keeps chomping away. He does this more to me then my dad who helps with the dogs. He will bite and squirm forever. It is like he doesnt hear me saying no and doesnt get it at all. I know he can hear because he hears a food wrapper and he is gone.

3. The only way to calm him down is to put his leash on and make he stay beside me. He then chews his leash and flips all around and grabs at anything he can ti chew. He has a bunch of new kong toys which he does play with.

4. This one worries me alot. He is a tiny little thing so I can restrain him b8t as he grows this could.get way out of control. He has serious food.guarding with my other dog. Not people. I give him his food.take ot away hand feed everything no issues. If.my other dog goes anywhere near where his food.bowl.was (I pick it up after the eat and feed him in another room) he will flip. Thank god.he was never loose when it happened because if he goes after her she isnt shy. In his crate once when he was eating she walked by and this was a very nasty growling barking and charging in his crate to get to her. If she walks by where his bowl was he will do the nasty bark and growl.

How can a tiny 5 month old puppy have these issues? I would never take him back to the shelter but I have to fix him. Not.many trainers around here and I am capable I train horses and can train him but am at a loss. Any tips ?? I have never seen a dog that doesnt understand no..nothing makes him sit back and so ohhh sorry or anything.