How does a person inherit this genetic disorder? Is it dominant or recessive? Is it genetic or chromosomal?

Tay Sachs Disease is an autosomal recessive disease and it is genetic.  The disease is caused by a mutation in the fifteenth chromosome.  The only way a child can inherit Tay Sachs is if both parents are carriers of this disease, meaning that they each have one mutated gene. 

http://nervous-system.emedtv.com/tay-sachs-disease/inheriting-tay-sachs.html

http://www.who.int/genomics/public/geneticdiseases/en/index2.html#ts