Well, since you haven't worked with frames before, I'll specify just in case you have trouble:
When in JED, select your 3do and hit "enter" to bring up the item editor window. At the base of this window, click the button labeled as "Add Value" and in the popup window type in "NUMFRAMES" in all caps. Hit enter, and this value will be added to the list of values under "+Layer" or "+Thingflags" depending on what you have there. For the "NUMFRAMES" value, put the number 1 in there, since these are all of the frames you should need. Next, hit the "Add Value" button again, and this time type in "FRAME" in the popup window (again in all caps). Press enter, and then select the new box in the item editor window and put in these values:
That specifies the vector and orientation of your object, being (x/y/z/) and then (yaw/pitch/roll). Place 360 in whatever orientation you like to get the object to spin continuously along that plane in a circle. Simply put a -360 to get it to spin in the opposite direction. You may have to tweak the 3do though, so that it spins around a pivot point that is in the direct center of the 3do, otherwise the motion won't be circular.
Then just specify the object number in the cog, select the speed of rotation, and even specify a sound to play while the object rotates, such as a fan noise.
Hope this helps!
