I live abroad and earn very little money. For many years I have not filed my taxes, but I would like to get my financial affairs in order, even though I know I have no tax liability for those years. I have the amount I earned each year and the exchange rate for December 31 of each year. In the past, I was able to complete my own forms as my financial situation has always been simple. I've searched the IRS site, but I can't figure out which forms I need to use to file for those missed years. Can someone help?

You will file Form 1040 for the year.
A U.S. citizen or resident must report worldwide income even when he or she does not live in the U.S. If your total worldwide income exceeds the filing requirement, a U.S. citizen or resident must file your U.S. tax return. If you paid taxes in the foreign country, you will claim credit for taxes paid in the foreign country by filing Form 1116 or can file form 2555 Foreign Earned Income Exclusion. Even if you have a filing requirement, the chances are you will not pay any U.S. tax or pay very little U.S. tax.
Another filing requirement is Form TD F 90-22.1. Your U.S. Tax Return: U.S. Citizen or Resident with Foreign Income