How do I look someone up on yahoo answers so I can see their questions and answers?

do an advanced search and enter the nickname of the person

up the top where is says 'Search for questions: then the search button - next to it 'advanced' click on that

I clicked on your avatar and I see that you are at level 4 with 2,782 points, and it makes me wonder how it is possible for someone to reach this level without knowing the answer to what appears to be a basic question.

Please, I am not criticizing you, just making an observation about how complex this system is for users to understand.

The easiest way is if you find a question that they have asked or answered. Click on their nickname and it will take you to their profile where all questions asked and answered are listed.

I would use the search for questions box and tap their name in there. something could come up to allow you to access their Q&A page

Click their the avatar or their question or answer.

Click their name or avatar. It'll take you to their profile.