On March 15, 2019 a gunman stormed into the Al Noor Mosque and then the Linwood Islamic Centre and opened fire on men, women and children who were at Friday prayer.
By the end of his rampage 51 people had suffered fatal gunshot wounds and a further 40 were injured.
The gunman later pleaded guilty to 51 counts of murder, 40 of attempted murder and one count of terrorism.
He was jailed for life, with no possibility of parole.
Maynard-Brown's first court appearance was brief and his lawyer sought an adjournment.
The 32-year-old was granted bail.
Outside court he spoke to Australian journalists.
He denied he was an extremist and claimed he did not intend to download the video.
He said it was "very wrong of me to have" done so.
"It was a mistake. I didn't even realise I had it.
"It was downloaded off of Facebook by accident."
News.com.au reported that Maynard-Brown denied supporting extremist views.
In addition he claimed to have changed his religion to become Muslim.
"I converted in October last year, so I'm Muslim, so the complete opposite to the monster in that video," he said.
"It's a complete misunderstanding."
Maynard-Brown is due to reappear before the court in August.