The 19-year-old and a friend helped carry supplies down a gorge to the victims.
Conrad, from from Somerset, said: “They were all in a very bad way – they had open wounds all over their bodies, and their clothes were completely torn off.
“Adrenaline kicked in and all I did was help carry equipment down and help the fire brigade down. The real heroes were the doctors that kept the survivors alive.
“I’m glad that I could help in some way, but I wouldn’t say I’m a hero.”
He said: ”At first everyone ran over to the cliff edge to see what had happened.
“Then a group of us started to collect things such as fire extinguishers, water, stretchers or really anything we could find that we thought might have helped.
“The walk to where the crash took place was very slippery and rugged so it made getting supplies down very hard.”
The survivors had managed to get clear of the helicopter when Conrad and his friend had reached the site.
Video footage emerged showing one woman fleeing from the burning helicopter.
Conrad and his friend stayed at the crash site to help until the injured tourists were rescued.
The Eurocopter EC130 helicopter plummeted 600ft into the rocky canyon at around 5.20pm local time on Saturday.
The tragedy claimed the lives of three Britons, Becky Dobson, 27, Stuart Hill, 30, and Jason Hill, 32, who were celebrating Stuart’s 30th birthday.
Stuart had been holidaying with his girlfriend Becky and his older brother when tragedy struck.
Grieving parents Rev David Hill and Sandra Hill, from West Sussex, said their sons will be “deeply missed by so many, many people”.
They said: “We have a large extended family and Jason and Stuart were always at the heart of it.
“If ever either of us came home after a difficult day, Jason or Stuart would be there with a smile or a hug, and that was all we needed to lift our spirits again.”
They continued: “We always did things as a family and as parents we feel blessed to have had them in our lives.”
Survivors of the tragedy Jennifer Barham, 39, newlyweds Ellie Milward, 29, and Jonathan Udall, 32, and pilot Scott Booth, 42, were airlifted to hospital and remain in a critical condition.
An investigation into the crash, and into aerial tour company Papillion, who owned the helicopter, has been launched.
Federal Aviation Administration spokesman Allen Kenitzer said the Eurocopter EC130 in question had crashed in “unknown circumstances” and sustained heavy damage.