Refrigerant System General Procedures

WARNING: This page is about a different car, the 2017 Mazda 3. However, it is still accessible from the selected car via links, so may be relevant.

Fully close the valves of the manifold gauge.
Connect the charging hoses to the high- and low-pressure side joints of the manifold gauge.

Fig 1: Connecting Charging Hoses To High- And Low-Pressure Side Joints Of Manifold Gauge
Courtesy of MAZDA MOTORS CORP.
Connect the quick couplers to the ends of the charging hoses.
Connect the quick couplers to the charging valves.