A DVD of police interviews with the seven-year-old, who cannot be identified because of her age, was played to the jury in Mark Bridger's trial at Mold Crown Court.
Five-year-old April vanished while playing with her friend near their homes in Machynlleth, Powys, Mid Wales, on October 1 last year.
The prosecution say April was abducted by Bridger, 47, who drove her off in his Land Rover Discovery and murdered her.
The film of the child witness's statement to police, recorded the day after April disappeared, was played to the jury as the girl watched on a video-link from Aberystwyth.
She appeared on the video-link with a white teddy bear and a mug of juice, with an adult who was partially off screen sitting next to her.
In the interview, the girl sat on a sofa playing with a brown rabbit cuddly toy.
She told police they had been playing on the Bryn-Y-Gog estate the previous evening when she saw April "by a Land Rover van".
"I saw her by the person that was waiting by the van," the girl said.
"She did not say she was going to go in it. I know they (April's parents) wouldn't let her go at that time.
"The man didn't take her in the van – she got into the van, having a happy face she had and she wasn't upset."
During her evidence, court officials, including Judge Mr Justice Griffith-Williams, did not wear their wigs or robes.
There were breaks every 10 or 15 minutes to ensure she did not "tire or lose concentration", the judge told the jury.
Former slaughterhouse worker Bridger, of Ceinws, claims he accidentally killed April with his Land Rover and cannot remember what he did with the body.
He denies abduction, murder and intending to pervert the course of justice by disposing of, concealing or destroying April's body.
The interviewing police officer then asked the girl to draw a picture of the Land Rover she saw and describe the vehicle in greater detail.
The young witness said it had been parked near garages on the estate and next to a BT van.
The officer asked which van April had got into, and the girl said: "The grey Land Rover."
She said: "I saw the man get out of the van.
"He was waiting outside the van for someone, I don't know who.
"I don't think it would be April he would be waiting for.
"I don't know why April would want to get into the van because her mum and dad told her not to get into vans like that.
"She wasn't crying, she was happy.
"She got into the back of the van and it just drove off the way it came and parked."
Asked what happened next, the girl said April's brother came over and said it was time for her to come home.
"Then I said what happened and I gave April's bike back to him and got on my bike.
"He came back and I told his mum. His mum called the police."
Asked to describe the man she saw April with, the girl said he had brown hair and a green jacket. She said he may have been wearing "bluey/black jeans".
"I can definitely tell you he had brown hair," she said.
"It wasn't that dark and I could see he had brown hair because the headlights were on."
She was asked to draw on her picture where the man had been standing and said he "got into the van when April got into the van".
Bridger denies abducting and murdering April Jones and intending to pervert the course of justice by concealing, disposing or destroying her body. The trial continues.
Edited at Telegraph.co.uk by Richard Holt