go to www.fincen.gov  and look for filing form 114. It can only be filed on-line.

However, I am not sure you need to report a pension/ retirement  account--- as long as the distribution is reported and taxed.  FBAR generally covers  bank accounts i.e. liquid assets.   FATCA ( form 8938 along with your return ) covers  specified financial assets  ( stocks, bonds and other financial assets that are semi liquid ) but not realestate  and such long-term  immobile assets.

form 114 is for the current year but you can go back if you like -- there is no tax effect for filing 114 but there is penalties ( onerous at that ) if you do not file when required to