Instructions can be found here

Enabling you to improve detail on the Heller kit and convert it to a late, cool version with two different engines, this 3D-printed set contains:

• 1 early F404 nozzles (only ones available suitable for the Rafale A, all other aftermarket sets I know of are later models with a cut on the aft part of the petals)
• 1 M88-2 nozzle (only ones available suitable for the Rafale A, all other aftermarket sets I know of are later models with a different nozzle-to-fuselage adjustment ring)
• 2 exhaust ducts (one for each type of exhaust)
• 2 afterburner flame holders
• 1 decal sheet for the left tail/aft fuselage “M88-2” specific markings