Computer simulations have become widely available to support geometric learning; however, the type and amount of guidance, as well as the freedom to engage in self-directed learning that should be allowed for children from differential socio-cultural backgrounds, have not yet been clarified. On the basis of the cognitive theory of multimedia learning and cognitive load theory, we varied guidance -- in relation to representation and manipulation -- between two levels (high and low) to form four conditions. We investigated 152 fifth-grade students with various socio-cultural backgrounds (80 were non-indigenous and 72 were indigenous) to explore the interaction effects of guidance on their learning of area-related concepts using a computer simulation--based environment. The results indicated that the learning performance of children from various socio-cultural backgrounds interacts with four experimental conditions at different guidance levels. More specifically, the indigenous children outperformed the non-indigenous children in highly directed learning environment, but the non-indigenous children outperformed the indigenous children in learning environments that entailed a high degree of exploration. Children from different socio-cultural backgrounds also exhibited various patterns of germane cognitive load. Finally, we discussed future study directions based on cognitive and socio-cultural perspectives for simulation-based learning environments.