Hi. This is a parts pack that uses the half size MK3 parts system like can be found in Airplane plus and is compatible with those parts.
Provided are parts to make the equivalent of a Huey helicopter and a Chinook troop or cargo helicopter with a loading ramp.
You can mix and match to make several variations.
Included is a rocket pod that uses the fireworks system, and you should adjust it once attached to get the effect you want.

The engine bases that sits on top of the fuselages are a hinge and require that "Breaking Ground" be installed for functionality. The main rotor attaches to it's top node and this allows the rotor to be tilted in flight for stable horizontal flight.
The tail planes are fully functional and as such create drag on vertical movement when rising and descending. The Huey nose is designed to exactly counter the drag at the other end and needs to be attached when the tailplanes are so that the craft doesnt pitch violently when moving vertically. The nose and the tail sections also have adjustable ballast so that once you have built your craft you can balance it so that the centre of thrust from the rotor goes straight through the centre of mass.
The Chinook doesn't have tail planes and empty is usually balanced, the cargo tail has the ballast system. The external fuel tank that attaches to the bottom and gives the fuselage the Chinook look is also a lifting surface, but as it is central, it doesn't cause the uneven drag. Having some lifting drag on the helicopters has been found to make them more stable.

Being that the Chinook is a heavy helicopter, it's rotor has a small spool up and down delay and so when taking off and landing you should allow for the time it takes to react, especially for landing so that you don't hit the ground hard by waiting too long before throttling up to slow your descent. Half throttle is usually enough to get most loads off the ground.
The Huey rotor is a bit more responsive but not as powerful.
Everything has nodes for click and connect. Be sure to check the Centre of mass and thrust before launch and adjust so they are through each other.
Type Huey in the part search for all the Huey parts and Chinook for all the Chinook parts.
I hope you will have some fun with this.