Definitely ignore the tantrums, they’re just attention seeking games. I take away a favourite something as punishment. A toy, book, DVD, bike….your choice. Time out is an option too, but not in his bedroom where he can play with his toys

ignore the tantrums as they know if it goes for long enough your will either give in or get angry. My son was the same and it took over a month for him to get use to the idea. We have ahuge sheet stuck on the wall with the house rules. WE all sat down one day and discussed the rules and wrote them down. Everytime the kids broke one of the rules it was pointed out the rule has been broken and there will be consequences. its taken a while for them to get use to it. but it works