You will either need a 3D printer or a CNC machine depending on the material you choose to use.
Step 1: Step 1: Open Solid Works
1. Open a new part.
2. Select the top plane and click "normal to"
Step 2: Step 2: Getting Your Drawing Started
2. Sketch a rectangle and dimension it to 1.5in x 3.5in
3. Click the "extruded boss/base" button and the select the rectangle that you just created.
4. Set the depth to 0.35 in.
Step 3: Step 3: Creating the Walls
2. Make a square with the dimensions of 3.5in x 3.5in
3. Click on the boss extrude button and set it to a depth of .32in
4. Repeat steps 1-3 on the other side.
Step 4: Step 4: Smoothing the Edges
2. Select all of the edges except for the base edges.
3. In the property manager set the fillett diameter to 0.10in
Step 5: Step 5: Custom Lettering
2. Open a sketch on that plane and click the "text" button
3. Enter your custom text and select where on the face you want to place it.
4. Extrude cut it by selecting the text and click the "Extruded Cut".
5. Select "Through all" in the drop down box and the select ok.
6. Repeat steps if you want to put other custom letters or designs.