plot of 3D array and drawing cylinders

Dear friends, kindly help provide these solutions.
1) how can I plot the elements of a 3D array say A(21,21,21) of 21-by21-by21
2) How do I display(in 3D) a cylinder. the coordinates of the bottom and top positions and the radius are known. How do I display the cylinder? example I want to display a cylinder with bottom (2,3,4) and top (5,1,6) with radius 7.

actually, I want to display many cylinders but if I learn how to do one, then I can do many.

Thanks