Orbital configuration is just how many electrons are in each orbit of the atom. The electons fill in a specific order which is by spfd and period on the periodic table. Two electron go in the s orbital, 6 in the p, 10 in the d and 14 in the f. This website shows the filling order, each box on the periodic table represent a spot filled by an electron. So for example if you had to write the electron configuration for Boron it would be 1s2, 2s2, 2p1. The 1s2 corresponds to the H and He box in the 1st period. The 2s2 corresponds to the Li and Be box in the 2nd period and the 2p1 corresponds to the B box in the 2nd period.