Create a rectangular solid of dimensions 3 x 2 x 1.5 inches. 

Sketch a rectangle on the front face with the dimensions as shown:

Extrude the sketch .75 inch, joining it with the base feature.

 Adding Chamfers

We will apply chamfers along various edges of the block

Choose Chamfer from the ribbon.

The top left is the button for the Distance chamfer. This creates a new face at an equal distance along the two faces that meet at that edge. We will use that on the interior edges. Make the distance .25 inches and choose the edges shown. You may need to rotate the part to get the four edges indicated.

Click OK.

Notice that the inside edge has had material added to it to strengthen the intersection of those faces.

Distance and Angle Chamfer

Open the Chamfer tool and select the second option, Distance and Angle.  The distance chamfer we did in part 1 will always be a 45 degree angle.  The Distance and Angle chamfer will allow us to change that.

Create a .25" distance and 10 degree angle chamfer along the top edges of your shape as shown.  You will need to select the side face first then the corresponding edge.  Do this for all four sides.

Notice that material is removed from the edge, in unequal distances from the faces. 

Two Distance Chamfer

This time choose the bottom left button: Two Distances. This chamfer creates a face at different offset distances from the edge chosen. 

Create the following two distance chamfers on the two longer faces as shown.

Distance 1 = .25"

Distance 2 = .75"

Save as "Chamfer Part 1"