I made some massive mistakes with my son in the early days.
I used to shout and scream and dish out punishments and sanctions.
Nothing changed.
And we all felt miserable.
I went to tons of training sessions and read up all I could on ADHD.
There were many children I taught with ADHD and they all had one thing in common:
They were desperate to behave and to be liked.
Over the years I have realised that if we change our reaction and make the environment suitable, we can massively change the behaviour.