Step 1) Crate a 2.5 by 2 rectangle and use Corner, centered at origin

Step 2) Add 2 points and make them midpoints:

Step 3) Add a construction line between the midpoints (link)

Step 4) offset the perimiter by 0.25

Step 3) Extrude the outside only:

Step 4) Add a 0.1 Chamfer to one side:

Step 5) On the other side, add a small filet.

Step 6) Play with the chamfer and fillet(increase sizes) until you understand the difference. In your google doc paste a screenshot of the 3 shape so I can see the filet and the chamfer . And explain the difference, physically, between the 2