Distinguishing is simple due to the episodic reality of bipolar. All the time or some of the time?

ADD/ADHD is an all the time thing. There are not periods where it is seemingly better or non-existant or much much worse. It is a continual issue.

Bipolar disorder? Off and on. The attention problems that come with mania or depression go away with mania and depression. There are periods of normalcy and during those times, no ADD/ADHD.

Those quizzes on this site are not helpful because symptoms overlap. If you have one disorder or even think you do, you'll find you "qualify" for a variety using multiple choice quizzes. The context of why you chose A doesn't matter. A is 5 points. Even with the human element, psychological diagnosis is just about recognizing a cluster of symptoms (often normal experiences and behaviors) and throwing a guess. So, they say you've got ADD now, no big deal. Swallow some Ritalin and see if that helps or makes things worse for you.