Hi, I have a very serious problem with my 4month old Maltese puppy.
I’m trying to train him to pee and Poe in one spot .he loves carpet ,so I placed a special carpet for him .but his doing it sometimes there and sometimes on the rest of places no matter carpet or marble.
I tried with given him whenever his doing it on the right place praises but it didn’t work.
Then I tried on top of it, if his doing it in the wrong place to put him for a while in his case .but it’s not working either.
Please help me.

Bad idea putting a carpet square for him to potty on.
He is not going to know the difference between that piece of carpet and the rest of the house!
By praising him when he is going on the carpet square you are effectively praising him for going on any carpet.

If you do want to train him to go to a specific spot inside buy some puppy training pads, they have a different texture and smell than carpet and the puppy will know that it is different... not just another patch of carpet.
They are a cloth pad with a plastic backing so the mess can't soak through to your floor underneath.