To enter in to the 0231 field you must go through an interview process with a minimum of an E-7 in the 0200 field and meet with their approval. After that you must qualify for at least a SECRET Clearance to attend NMITC the Intelligence School. You must past the 3 month course at NMITC then you will be assigned to a unit. While at the school you will have a back ground investigation ran on you and you must qualify for at least a Top Secret clearance. A Top Secret Sensitive Compartment Information clearance is preferred.