'Number of examples' in the video lectures

Could you please confirm what the ‘Number of examples/samples’ refer to ? is it the number of rows (i.e different samples) or a number of columns (i.e. features/variables) ? In the video it is mentioned X1, X2, … Xm as ‘m training examples’ with nx features but the neural network figure shown in the video lectures shows input nodes as X1, X2, X3 (as per my understanding it cannot be different samples).

Each row of X is a different feature
Each column of X is a different sample