There are five categories to choose from.

Featured: This is for featured work.
Central Mexico: This area is where you can add artwork inspired by or depicting the Aztecs, Tlaxcallans, Toltecs, Teotihuacan, Otomi, and other people of the region.
Maya Area: This area includes Belize, Southern Mexico, Guatemala and parts of El Salvador and Honduras. This is where you can add artwork inspired by or depicting the Maya and a few of their lesser known neighbors like the Lenca, Xinca, and others.
Other Mesoamerican People: This is where you can include cultures from Mesoamerica that are not in the Maya region or from Central Mexico. These regions are:

in Mexico:
-Oaxaca - the Zapotec, Mixtec, Chatino, Chontal, Chocho, Mixe, Zoque, Mazatec, Chinantec, Huave and other cultures.
-Guerrerro: the Xochipala cultures, the Amuzgos, Yopi, Matlazinca,  Cuitlatecas, Ocuitecas, Mazatlecos, Tlahuicas,  Coixcas, Tepoztecos, Mixtecs,  Tolimecas, Chubias, Pantecas and others
-Gulf Coast - the Olmecs, Huaxtecs, Totonacs, Veracruz cultures and others.
-the Northwest - the Chichimec groups, Purepecha, the people of the Michoacan, Sinaloa, Colima, Jalisco, Nayarit and other cultures.

El Salvador: the Pipil, and Lencas of El Salvador.

Honduras: The Lenca of Honduras and their northwestern neighbors.

Nicaragua:
-Pacific Coast: The Nicarao.

Costa Rica:
-Northern Pacific Coast: The Chorotega, Nicoya.

Other: If your work has no regional focus, and/or is more of a general 'Mesoamerica' inspiration than it goes here. If the artwork contains people from different regions it can also go here.

If in doubt on what is considered Mesoamerica by most scholars, see this map: [link]

Lastly, as a final note: please do not submit South American cultures. Mesoamerica=Middle America. South America=SOUTH. I love those cultures, but this group is not about them, Thanks.