Flying a GPS approach depends a lot on how much the company is prepared to pay for the right connections. For example a Bristow 332 wil give the GPS presentation on the HSI but the course to fly has to be set manually and the distance to go has to be read off the Trimble unit by the co-pilot. In China GPS approaches are not approved as yet but when they are Chinese 332s will already have automatic course setting and distance to go on the HSI. ie when you reach a turning point the Beam Bar rotates to the next course and the distance to go comes up on the HSI. Same Trimble, same HSI, just more interested greenies.
Sit back, plug in the Nav function and watch your instruments tell you how they are doing the approach for you.