Start a new part and then a new sketch. Use the XY plane for your sketch:
While in sketch mode draw two circles on it, then exit the sketch:
Now extrude, you may have to select the "profile" as being the area between the two circles:
In the browser select the yz plane and create a new sketch there:
Like this:
Now you have to put some points in the sketch which can be used as hole centers. To do this make sure that center point is highlighted like this:
Now when you use the point command the points you make can be used as center points:
Putting 3 points in the yz sketch will look like this:
Click on Finish Sketch, you'll return to the 3D part view. Now click on the Hole icon and you'll get something like this:
