Your doing a saucer... Ok, that's a simple one.
First off, a few things to remember. MS3D is a Game level rendering program. MS3D is limited in the maximum number of polies it can supprt on a single model. If you have a high end system, then 64,000 is the upper limit. If you are running a lower-than-high-end system, consider you max to be 32,000. If your doing a model for use in a game, 16,000 is the max number of polies. Also, one more note, the more polies you have, the higher risk of suffering a crash with the program.
Now, the maximum slices to get a "close to" perfect sphere is 32, as with 32 for the stacks. The basic shapes will not render any more than this. So, make a 32x32 sphere. Now, to increase this, you can open your tools menu, then open up the DirectX Mesh tools (if this is not installed on your ms3d, then go to the website downloads and get it, and install it). Now on the menu of that window, you have little "red triangles" marked 2x, 3x, 5x, and 7x. Now you can click the 2x icon. after a few seconds, the sphere will become a 64x64. DO NOT USE 3X, 5X, or 7X. You Will Suffer a crash if your system is not high end. Also, do not do the DirectX tool more then once, as each time, the slices and stacks it generates become a little more "out of sync" with the geometry of the sphere, and that's another quick tutorial to fix (however, if your system can handle it, then you can do the 2X twice. This will render a 128x128 - 31,744 poly sphere). You can use this on any shape. A saucer would be best made out of a cylinder.