She has other videos that are more clear but I like this one about the best. After watching some other videos and reading her comments, I'm even more impressed with what she does.
On her left hand, she's missing her thumb and most of her two middle fingers from a childhood accident. She plucks with her index and pinky. Because her left hand is only good for plucking (not fretting), she plays left handed.
She learned how to play on right handed basses, playing them upside down. Now she has a left handed bass but has it strung upside down because that is how the strings were when she learned.
She is playing all of this. She has effects and a looper. She starts out by playing the backing tracks, recording it and then looping it. She keeps adding to the backing tracks until she starts playing the song.