See
How to use ArcGIS samples
for help on compiling, setting up the debugger, and running the sample.
If the sample has associated data, you will find that the sample's zip file includes a "data" folder alongside the language folders.
However, you will need to update the sample to point to the location of the data once you have extracted all the files.
Compile and register the .dll.
Start ArcMap and load some data.
Customize ArcMap and add the shape constructor to the Editor toolbar.
Select a feature template and a construction tool.
Click the Angle-Angle shape constructor. Add three mouse points to view the next edit segment.