Note the type of microform: microfilm, microfiche, or microcard/microopaque.
Write the call number.
Look at the full record to see if the microform belongs to a series. If so, write the series name in its entirety and the microfilm reel number and location on the reel if provided.
If information is not in the Series field, look at the notes fields, especially the Reproduction note, to find a microfilm reel number or fiche number.
Give this information to the government information staff person at the desk to help you locate the item since different series have different filing rules.