difference detween ¨that¨and ¨who¨

the difference between that and how is that in a sentence like, my brother brought me that pencil case from Argentina is telling something like if you were  pointing at something or someone and the word who in a senctence like, do you know who took my notebook is like telling who as a person.
run on sentance: a run on sentance is two sentances that are combined together without separationg by a period, comma conjuction or semicolon.