You are the president, the other is the second president, a secretary and a cashier. One person can take two positions. The choice of the name is important, It has to be in Spanish or invented and it may not exist already, what can be checked easily in the register. The lawyer will check it for you. The new law requires a perfect book keeping and they punish hard, if someone does not keep them up to date.
Some lawyers offer to buy a company that already exists to speed up procedure.
Better take your time for founding your own. If your company is registered, you can do all kind of legal business, except buying properties from the governement. There are several ways to make money in Costa Rica, but there are even more to loose money fast. Many people get cheated again and again so watch out. Even friends of mine lost many thousands of valuable dollars, because they did trust too much.