Hashem Abedi, 22, was allegedly linked to the bombing by a scrap of metal found at the scene of the carnage.
The court heard that he bought screws and nails for deadly shrapnel and used fake online accounts to purchase two of the three chemicals to make explosives.
His brother Salman Abedi, 22, then detonated the large device as music fans were leaving an Ariana Grande concert at 10.31pm on May 22 2017.
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Opening the younger brother's trial at the Old Bailey, Duncan Penny QC said: "The prosecution's case is that this defendant is just as guilty of the murder of the 22 people killed as was his brother.
"He is equally guilty of the attempted murder of many others and in doing so he was guilty of agreeing with his brother to cause an explosion or explosions of a nature likely to endanger life."
The court heard how Salman Abedi, carrying the bomb in a rucksack, joined the throng of parents and families picking up young concert-goers in the foyer of the 21,000 capacity venue, before detonating.
Mr Penny said: "Twenty-two people - men, women, teenagers and a child - were killed, 28 people were very seriously injured, a further 63 people were seriously injured, 111 others were also hospitalised," he said.
"The bomb which was detonated was self-evidently designed to kill and maim as many people as possible.”
Mr Penny said the explosion was the result of months of planning, experimentation and preparation by the brothers.
Hashem Abedi had allegedly assisted and encouraged his brother by obtaining chemicals and sourcing oil cans from his work at a takeaway in Greater Manchester, saying he wanted them for scrap.
His fingerprints were later found on scraps of metal from the cans at the family home in Fallowfield, Manchester, and at his brother's rented flat in the city centre, the court heard.
Mr Penny said the cans played a "pivotal role" in the design of the bomb container.
The court heard how Salman and Hashem Abedi had rented a flat in north Manchester to prepare explosives.
After the bombing, Hashem's DNA and fingerprints were found at the address as well as traces of explosives.
The brothers used Amazon accounts of others to order the chemicals to make the bomb, jurors heard.
The pair, whose parents are Libyan, had allegedly begun to show "some signs of radicalisation" in the years before the bombing, Salman more than Hashem, the court was told.
Hashem, originally from Manchester, denies 22 counts of murder, attempted murder and conspiring with his brother to cause explosions.
Five people from the North East were among the 22 who were killed.
They were; Chloe Rutherford, 17, and boyfriend Liam Curry, 19, from South Shields; Hartlepool born Jane Tweddle, 51; and Philip Tron, 32, and his partner’s daughter Courtney Boyle, 19, from Gateshead.
Members of the victims' families attended the trial, which is due to go on for eight weeks.