Hi Lish - that was created using Construct / Loft.

I didn't use a guide for that one - in MoI the Loft command is for creating a surface through cross-sections without any additional guide curve. Using a guide curve as a path in MoI is called the "Sweep" tool instead of Loft.

Here are the steps - first I drew 3 curves in the side view (I used the Right view this time), using Draw curve / Freeform / Control points:



Then I switched to the 3D view so I was looking at the curves like this:



Then I dragged the curves apart to position them:



Then select all 3 curves and run Construct / Loft:



The hole was cut by drawing an additional curve in the front view and then selecting the surface and running Edit/Trim to cut the surface with the new curve.

- Michael