Welcome, Bob.
You pose a challenging problem. This is not simple, beginner-friendly sketching up. You might want to practice sketching up something easier, such as a house. Don't start with a carefully drawn, Arc-based horseshoe. Start with something like my horseshoe. That said, here goes.
I'll illustrate a technique with a "horseshoe" that won't win any prizes. Draw yours a bit too long as we'll cut it back. I've used a 10% slope (and suggest that you start that way, too) as 3% is a bit too subtle. First you PushPull your horseshoe up into 3D, with straight sides. With the Scale tool (Google for a video tutorial) you expand just the top, 10%.
Draw a line to close the horseshoe and PushPull up the inside. Use the Scale tool again, this time to shrink the top of the inside by 10%.
![horseshoe01.jpg](/uploads/imported_attachments/dJfW_horseshoe01.jpg)
Ctrl+A to select all, right click and Group. Draw a rectangle a bit larger than the horseshoe. PushPull it up. Triple-click the new box. Move it into your horseshoe enough to cut off the excess length. Leaving the box selected, right-click your horseshoe and explode it. Then Edit/Intersect/Intersect with Model.
![horseshoe02.jpg](/uploads/imported_attachments/uj30_horseshoe02.jpg)
Now it's time to clean up. Delete all the lines that aren't part of the finished horseshoe. DO NOT use the Eraser. Click a line to select it, scratch your head to decide if you really don't want it. Press Delete if it's not a keeper.
![horseshoe03.jpg](/uploads/imported_attachments/UAyM_horseshoe03.jpg)
Connect the outside lines to the inside lines to get the shape you want. Delete the lines you don't need.
![horseshoe04.jpg](/uploads/imported_attachments/rVYo_horseshoe04.jpg)
When you get here, you're ready to go back and sketch up a horseshoe that might win a championship. Good luck!