libfprint includes several simple functional examples under the examples/ directory in the libfprint source distribution. Those are good starting points.

Usually the first thing you want to do is determine which fingerprint devices are present. This is done using the FpContext object.

Once you have found a device you would like to operate, you should open it. Refer to device operations. This section also details enrollment, image capture, and verification.

That should be enough to get you started, but do remember there are documentation pages on other aspects of libfprint's API (see the modules page).