This page will give a breakdown of best practices for using parachutes for recovering a rocket. Improper setup of the recovery system can result in harm to the vehicle and possible unsafe conditions for people on the ground.
For a typical dual deployment rocket, the body tube will separate at two different locations: between the nosecone and the upper body tube and between the upper body tube and the lower body tube. These separation points must be secured with shear pins, which are small plastic screws designed to shear apart when the deployment system activates, allowing the tubes to slide apart.
The rule of thumb for putting the parachutes into their compartments at these separation points is that the drogue parachute should go in the lower compartment (between the lower body tube and upper body tube) and the main parachute should go in the upper compartment (between the nosecone and the upper body tube). The reason for this rule goes back to the shear pins. Consider the two possible configurations:
Configuration number 2 is the more ideal scenario, thus the reason for it being the rule of thumb.
In order to fit into the body tube, parachutes must be folded up to take up less space. The folding process is a specific one and must be done right, or there is a risk that the parachute may not deploy correctly. The specific folding instructions vary between manufacturers, but are generally similar. Below are links to the folding instructions for two manufacturers from which ARA has purchased and used parachutes before:
Depending on whether the vehicle uses black powder or CO2 for separation, the parachutes may or may not require a flame bag for protection. Flame bags are designed to go around a folded parachute to protect it from the heat and corrosion associated with black powder separation. A flame bag is generally not required when using CO2 because only a small amount of black powder is used to puncture the CO2 cartridge. The actual mechanism that separates the body tubes is the inert CO2 gas, which is harmless to the parachute material.