A method of controlling a preparation instrument which prepares a detection composition used for detecting a target nucleic acid molecule in a specimen, 5 the method comprising: displaying a plurality of option fields comprising a type of detection composition and a type of target nucleic acid molecule desired to be detected on a display so as to determine a desired detection composition, wherein the detection composition includes a nucleic acid extract and a reaction solution for nucleic acid 10 amplification; receiving user selection information from each of the plurality of option fields; determining a work data file based on the selection information, wherein the work data file (510, 520, 530) comprises a work list comprising time-series work actions required for 15 preparing the nucleic acid extract and/or a work list comprising time-series work actions required for preparing the reaction solution for nucleic acid amplification, and comprises instruction name information and instruction processing information used for implementing the work actions in the preparation instrument; searching for an instruction that matches the instruction name information 20 allocated to a work action from an integrated instruction file, according to the order of the work actions included in the determined work data file, wherein the integrated instruction file comprises all instructions used for implementing all work actions that are desired to be operated in the preparation instrument, and the instructions comprise instructions for moving a pipettor, which performs pipetting in the preparation instrument, upward and downward, leftward and rightward, and forward and backward, and for dispensing, aspirating, or transferring a liquid; and performing control such that the retrieved instructions are processed according to the instruction processing information and the work actions are 5 implemented in the preparation instrument. displaying a plurality of option fields comprising a type of detection composition and a type of target nucleic acid molecule desired to be detected on a display so as to determine a desired detection composition, wherein the detection composition includes a nucleic acid extract and a reaction solution for nucleic acid 10 amplification; receiving user selection information from each of the plurality of option fields; determining a work data file based on the selection information, wherein the work data file (510, 520, 530) comprises a work list comprising time-series work actions required for 15 preparing the nucleic acid extract and/or a work list comprising time-series work actions required for preparing the reaction solution for nucleic acid amplification, and comprises instruction name information and instruction processing information used for implementing the work actions in the preparation instrument; searching for an instruction that matches the instruction name information 20 allocated to a work action from an integrated instruction file, according to the order of the work actions included in the determined work data file, wherein the integrated instruction file comprises all instructions used for implementing all work actions that are desired to be operated in the preparation instrument, and the instructions comprise instructions for moving a pipettor, which performs pipetting in the preparation instrument, upward and downward, leftward and rightward, and forward and backward, and for dispensing, aspirating, or transferring a liquid; and performing control such that the retrieved instructions are processed according to the instruction processing information and the work actions are 5 implemented in the preparation instrument.