Hello @stew985,
Welcome to Fusion 360 community forum. Thanks for posting!
As I understand, you are trying to create holes in the sloped face of the body and you want to put them in the desired position.
You chose the sloped face of the body as the face to create the hole in. In the next step, you added the edge of the bottom (or the top), horizontally oriented face of the body as the reference (see the attached screenshot). By doing that, you were able to define the distance between the center point of the hole on the sloped face and the referenced edge.

As a result of changing this distance, the location of the hole changes. This way you can put the hole in the desired position in reference to the edge of the top or the bottom face.
Should you want to position the hole randomly, you can move it by dragging the center point. An alternative might be creating a sketch on a tangent plane that @aaronkcap mentioned.
You can find a description of the Hole dialog box here.
If this answers your question, please let us know by marking this post as a solution. Enjoy using Fusion 360!
Best regards,