"There is tour guider in Arusha"
Translation:Arusha kuna mtembeza watalii
kutembea = walk
kutembeza = to walk (eg. a dog), to guide, to take on a walk [the causative form of kutembea]
One way to talk about someone who does something, especially if you have a verb and an object like this, is to just put m- on the beginning of the verb ... it's automatically a noun meaning "one who Xs Y", so mtembeza watalii is a tour guide = one who takes tourists on walks
What is a "guider" there is no such word in English. I am either a Tour Guide or a Tourist Guide.