Artificial neural networks (ANNs) are a type of statistical model that learns to make predictions given data. They are assembled of layers of single neurons. These layers are are interconnected using specified functions.
For a basic understanding I suggest the following sources:
- Deep Learning Book (pp. 13) by Goodfellow, Bengio and Courville
- Deep Learning State of the Art video series by Lex Fridman
- Neural networks video series by 3Blue1Brown
- Pattern Recognition and Machine Learning by Christopher Bishop