The figure below illustrates a 2x2x1 supercell of transition metal-doped CrI$_3$ monolayer. The red, green, and black atoms represent Cr, I, and transition metal atoms, respectively. I want to calculate the energy of this doped monolayer in the AFM configuration, but I don't know how to set it. Please I need your urgent help on how to set the spins of the atoms for the AFM configuration for this doped monolayer. I mean which ones to set up, and which ones to set down? should I increase the supercell size?