If you are working with a flat surface you can make a sketch and add the points to the sketch using project points onto sketch plane (sketch function)then creat circles at each piont in the sketch. Extrude the sketch and subtract from the main body. You can use this sketch for your next hole...
The simplest way to produce models is o use features such as blocks and cylinders, then use feature operations like grooves, pockets, chamfers, blends, tapers, etc....
These are simple, easy to learn, very effectiveeasy to manipulate and the basic functions of UG.
