The first section of this user guide profiles the OHTS, describing its technical specifications, its purpose, how it was developed and tested, and how program and case managers should prepare to use the OHTS. This guide advises that the OHTS is designed for use with Microsoft Windows Excel for PC. The OHTS assessment and stored client data are fully functional in Excel for MacOS and IOS, but data editing and visualization are not operational in the current version. This guide recommends that programs for human trafficking survivors review how the OHTS fits the program's evaluation activities and goals; assess the adequacy of program resources for OHTS use; plan for its implementation; and train staff in how to use the OHTS. Guidance for using the OHTS addresses who should complete the OHTS and when and how case managers should complete the OHTS. Another section of this user guide reviews the features of OHTS client data displays. Topics covered in this section are how the OHTS displays client data, a client single assessment summary, a client multiple assessment summary, program level summary, and how to do more with OHTS data. The concluding section of the user guide defines the 14 key terms for the types of survivor services evaluated by the OHTS.