Newbie - Hi, a little help please

[Jisp]

Hi all. I'm very new to SketchUp and new to the forum. In order to try and teach myself I'm trying to model the chassis of an old electrical toy car. I'm almost done and have found a problem I can't fix. In the first pic, the areas with the blue X are holes that originally looked like those with the red X. I'm trying to duplicate the holes in the areas with the red X. I'm able to select one side and delete it but when I try to select the other side the entire lower section of the car is selected, not the smaller shape. Hard to explain in words so perhaps some pictures will help. Any assistance is greatly appreciated, thanks.

[TIG]

If you Style has Profiles ON and they are set to be thicker than the normal line width you might see that the outline of the second 'hole' has not punched the face - unlike the first set of edges.
Examine it in closer detail.
If there's a missing line [or more] add it [them] and the separate face should form and then be erase-able.
Or try selecting it and right-click context-menu to Intersect it with the model - this might force the edges to form their own face, which can then be deleted.

[Jisp]

Thanks for such a fast reply Tig. I set the Profile to ON and thickened up the lines a little. Gave me a much better idea of what was going on. There was indeed a line missing along the inner most edge of the section I needed to define. While I couldn't quite get the newly drawn line to go exactly where needed (slight offset), I was able to more/less achieve what I was trying to do. No doubt I just need to "play" with it a little more to figure it out but at least I'm now pointed in the right direction.

Thanks again!