You can try the modern way, you buy Maseca (this brand is the most popular in the country, and used as a generic term) at any local market, mix it with water and you make tortillas, or you can make them the traditional way. They taste similar, but not the same and costs can make the difference.
Tortillas in Guatemala are not made in machines, but hand made in torillerias or at home, and not stores or supermarkets. When made at home, they are made from Maseca.
First you mix about a pound limestone with quarters of water, until is a thick mixture, you can keep this mixture to use several times, or you can make less, i guess.
Then you find a cooking recipient, that will hold the corn, first you put some water in, about two quarters per pound of corn, and a teaspoon of the limestone mixture for each pound, and then you cook it, until it softens a little, but not much, the corn loses its cover and you must be able to easily cut it by half, but it should not be too soft that it will become a mass.
You let it cool at least three hours, or overnight, then you wash the grains.
Then you take it to a mill, and they will make a mass adding a little water, but not much.
Then you make the tortillas, first you make a small about one inch round ball, and with your hands, like clapping, make a thin round disc, using a little water if it is too hard. Then you can put it in a metal sheet with some oil, clay surface with lime or a teflon covered surface, turning it like pancakes two times, and you are done.