What exactly do I have to do in order to get them papers, and how old do I have to be if I'm only 18?

First of all, you have to be 21 in order to petition for your parents. Secondly, you can only do so, even when you are 21, if your parents entered the US lawfully and can document that lawful entry. If they did not enter the US lawfully, under the current immigration laws they are not eligible to legalize their status within the US but would have to go back to their home country. However, as soon as they depart the US, they trigger an automatic 10 year bar to reentry which can only be waived by a showing of extreme hardship to a US citizen spouse.

Unfortunately, you have to be 21 to petition your parents.

You cannot file green card for your parents until after you turn 21 years. There might be other immigration options for your parents, but you need to consult with an experienced immigration attorney who must have further details about your parents.

You have to be at least 21 years of age to petition for your parents. The petition is filed on form I-130, and you will need to file one for each parent.