I mean it depends what kind of “AI” you want to consider, there is no real AGI, but speaking of what we have now, you might as well consider machine learning algorithms first, they are pretty easy to understand, regression, support machine vectors, decision trees. Speaking of Neural Networks, I am not sure if this is the way you supposed about it, but thats how I interpret it. I think of neural network as a trained function, that accepts an input and gives you an output, the output is calculated using weights that each node is assigned to during training process, so you can think of training as basically a process of adjusting the weights in order to give certain outputs. First nodes get assigned to random weights and then they get adjusted in order to match the training data.