The parents of a Vietnamese man paid £13,000 for a "VIP" smuggling trip to Britain along a route where 39 migrants died, a court has heard.
Prosecutors allege the man, known as Witness X, was on one of two successful cross-channel runs before the deaths on 23 October last year.
He told jurors he arrived in Essex weeks earlier with 14 other Vietnamese migrants he had met near Paris.
Four men are on trial in connection with the deaths.
Less than two weeks after the anonymous witness's 11 October crossing, 39 Vietnamese nationals were found dead in the back of a lorry in Purfleet, Essex.
Prosecutors say both operations were organised by the same people smugglers.
Witness X told the court there were two types of smuggling service, one where the lorry driver was ignorant of the human cargo and "VIP - where the lorry driver knows you are there."
He said he was taken from a flat near Paris on a 90-minute taxi ride to a field, where his 15-strong group was told to hide and wait.
An English-speaking lorry driver arrived and ushered the group into the trailer, he said.
If the driver knocked on the side they had to stand up and stand together in the middle of the trailer and "don't make a sound", he said.
Before arriving at a port, he said, the driver stopped to give them water and instructions on what to do if they needed the toilet.The sea voyage to Britain in the container took about eight hours, jurors heard.
When the doors were finally opened in the UK, the witness said, some people with European accents helped them out and told them to "move fast" into black cars.
The man was then held in the second-floor flat of someone called Phong until his family had paid £13,000 into an account in Vietnam.
He said he had learned about the crossing from a friend who told him to contact Phong through messaging app Viber.
Jurors were told that an examination of the witness's mobile phone placed it in Paris on 10 October and in south-east London the next day.
The court was also told about a white trailer parked by the one in which the 39 migrants were found.
This was the same trailer dropped off at Zeebrugge by lorry driver Eamonn Harrison and picked up by Christopher Kennedy at Purfleet in October last year, the court heard.
Witness X's thumbprint was recovered from inside, and lorry driver Maurice Robinson's prints were also identified on an Evian bottle containing urine, a brownie wrapper and two carrier bags.
Driver Christopher Kennedy, 24, from County Armagh, denies being part of a people-smuggling conspiracy with fellow haulier Eamonn Harrison, 23, of Mayobridge, Co Down, and Valentin Calota, 37, of Birmingham.
Alleged key organiser Gheorghe Nica, 43, of Basildon, Essex, has admitted the conspiracy but denies 39 counts of manslaughter, as does Mr Harrison.
The trial continues.