You asked

How do I help my teenager with ADHD or ADD follow rules and avoid behaviour problems?

It’s important to realise that your child will require additional supervision and more of your time than other children to learn how to practice responsible behaviour.
Break up desired behaviour into sections and let your child learn the consequences of his actions. For instance, if your teenager wants to stay out until ten o’clock, begin by letting him stay out until nine o’clock. If that goes well then allow him to stay out until ten o’clock. If, however it doesn’t go well move the curfew back to nine until he can responsibly stay out later.
Keep a controlled eye on your teenager’s behaviour outside the home, such as what friends he is with, what he is doing and when he will be home. Set clear rules for what behaviour you expect, what is and what is not permissible.
Expect to encounter problems, develop behaviour contracts for situations that may be potentially difficult, such as homework or being home on time. You and your child should be fully aware of what will happen if these rules aren’t kept. Punishments should be fair and consistent, with your child knowing in advance what will happen.
There should be certain rules which are negotiable and others that are not negotiable. You may find that your teenager is more compliant with rules that they have helped create. In order to help your child develop independence, gradually give them more of a say in decision making once they have proven themselves.

More questions

Your child will have an Individual education plan that outlines exactly what services your child will receive.
Any child who received special education resources or support in primary school will almost certainly be eligible for the same support in secondary schools.
If your child has been receiving extra help in primary school it is important to look for a secondary school that will suit his needs
There are significant differences between children who are slow learners and children who have a learning difficulty?
There are lots of things you can do to help your dyslexic child develop their reading skills.
It's perfectly normal for parents of children with ADHD to worry about their child's future. 
Teenager's with ADHD will require additional support and supervision from parents to avoid behaviour problems.
There is no single, easy way to treat ADHD. Treatment is made up of a mixture of medication, parent training, counselling and a special education environment.
ADHD is generally diagnosed when a number of the symptoms outlined before the age of seven and for a period of more than 6 months. 
There are many different behaviours which are characteristic of ADHD: