A tip from a group of horseback riders led to the rescue of Anderson at a remote camp spot near Morehead Lake, Idaho, about 75 miles north of Boise, Idaho.
"They were extremely quiet. Didn't want to engage in any kind of conversation, kind of had a bad look on their face," Mark John, one of the horseback riders and a former sheriff's deputy from Gem County, Idaho, told "Good Morning America" earlier this week.
Anderson wrote that she remained calm when she saw the horseback riders because she was afraid DiMaggio would kill them.
When the group returned home the next day and saw the report of the amber alert for Anderson, they notified authorities.
Authorities located a blue Nissan, owned by DiMaggio, covered in brush on Friday.
Anderson wrote that DiMaggio forced her to help him cover the car with branches.
Aside from answering questions about her ordeal, Anderson responded to well-wishers from around the world and thanked them for their support.
She also posted a photo of herself in bright yellow shorts and said she got her nails done on Monday -- pink for her mother and blue for her brother.
The Associated Press contributed to this report.