This is the Prometheus Launch Vehicle v0.7. It is a Multistage2 vessel simulating a possible realistic launch vehicle based on common core technology (Delta IV, Atlas V, Angara etc.).
To install, simply extract either to a temporary folder and copy the contents to your Orbiter directory (recommended) or extract the .zip file directly to your orbiter directory.
Also included is the Precision Guidance Stage which is a Spacecraft3 vessel designed to allow precise maneuvering with translation thrusters (which Multistage2 doesn't natively support). It also has a grappling point so it can be held near a space station while the payload is released.
The manual for this includes an extensive description on how to work the payloads as well as how to launch the vehicle. For launching, I strongly recommend Enjo's Launch MFD.
REQUIREMENTS:
Vinka's Multistage2 and Spacecraft3 (not inlcuded)
RECOMMENDED:
Launch MFD by Enjo