Now that your child has been diagnosed with ADHD, and you have done all your research, now it is time to sit down with your child and to talk to him/her about it. For this E-how, I will state "he". Ask him if he is in the mood to talk about it. You do not want to have a long in depth conversation about ADHD with a child who has ADHD.
Ask him what if he knows any thing about ADHD, and what his thought and feeling are on the matter. Does he know anyone in his class that has ADHD. You may be surprised to find out that he may have 3-4 other kids in his class who have it, are taking medication for it, and are succeeding quite well.
Now, explain to your child what ADHD is for the record, to clear up any myths that he may have heard about it. Tell him that it does not mean that he is a bad kid, that it is a biological issue, but counseling might help the matter. To prove your point further you can show him information on the internet which provides further empirical evidence that individuals who have ADHD, that their brain functions differently.
Make sure that he understands that while this is a challenge, this does not define him. This does not mean he is stupid, or that he has some major handicap. Also, talk to him about whether or not the doctor wants to put him on any medication. If he has any questions or concerns about the medication, tell him to write it down, so he can personally ask.
This is going to be an issue that your child will likely deal with for the rest of his life. He want to teach him the tools that he will need to manage this condition. Teach him that he is the one that will be eventually responsible whether or not he is managing it effectively.