(My reply posted before I finished it.) Every test has a protocol on how it's done. With some tests, there is a time limit. Some are read to the student. What the evaluator says is often scripted. Some assessments are rating scales where an adult (a parent or a teacher) answer questions where the choices are: never, rarely, often or frequently. These tend to be fill in the dot questions. There are HUNDREDS of normed evaluations out there and they each have their own protocol for administering the test. You can see if your local library has something that might explain how some tests work - it will be fairly technical. Parents will sometimes ask the psychologist to do test 'Z'. My response is, if the person doing the assessment knows how to do test 'Z', that's great but if they are more comfortable administering a similar test that tests the same thing, have them go with the test they know.
If you intend for your child to enter school this fall, now is the time to register with the school and request a sp ed evaluation. You will need to give your written permission for an eval as well as bring your child to school for the needed evaluations. No IEE at school expense until the school has an opportunity to do an eval on your child. You can share any medical evals that may have been done. Actually, you should tell the school what evals were done. Most evals cannot be redone within 12 months so what evals & when they were done are things the school needs to know. (Most school psychologists get the summer off so don't think they will do this over the summer.) Do things in writing so you have a paper trail.
Lastly, when a child has behaviors, I always suggest Ross Greene. I really need to put info on him into a file on the site but until then, you can go to livesinthebalance.org.