Since Tau2 is not environmentally sealed, the first step would be to build a protective enclosure for the camera. The enclosure would need to provision for mounting points. There would need to be a way to get power to the enclosure (and camera), and video from the camera out through the enclosure and back into the vehicle where it would be routed to a display.
FLIR does not offer an environmental enclosure for Tau2. PathFindIR II may be a better option since it is already sealed, and is intended for vehicle integration. The PathFindIR II Quickstart Guide provides information about the included components, as well as contents of the optional Installation Kit.