Completely new: how do I create and oval shape i. 2d?

Make a circle

Use Ctrl and Scale

Learn the basics: https://learn.sketchup.com/track/sketchup-fundamentals-part-1

Additionally, I always draw two sets of guides, one set for each axes X and Y such that you end up with a rectangle representing the extents of the oval.

Set 2 center line guides one in each direction, draw a circle centered on the intersection of the two centerlines and scale the circle using the Ctrl modifier key until the oval fills the rectangle.

Guides are an unnecessary step. Follow @mihai.s gif.

Start a circle, type your desired dimension, (radius). Start Center Scale the circle in one axis, type second dimension (diameter). Done.

Thanks for that explanation. I prefer graphic solutions for my little brain.

Strictly speaking, a scaled circle is an ellipse, not an oval, but that’s probably what you wanted anyway. An oval is made with two different pairs of pie slices butted together.

Make a circle > Draw the diameter with a line > Scale half of the circle (erase the diameter line)

Thanks, @RTCool!

Actually, I was thinking more in these terms:

Very similar but not exactly the same shape that have different methods of construction. When it comes to making things on an construction site, the oval is a be easier to construct, and lends itself better to parallel offsets like making a roadway, but it’s not quite the same thing as an ellipse. In SketchUp and other programs, it’s the ellipse that’s easier to make.