In "The Alcohol, Smoking and Substance Involvement Screening Test (ASSIST): Manual for Use in Primary Care" read sections 1 - 7 (pp. 1 - 10). This should give you a sufficient understanding of how and why the ASSIST and the ASSIST-Linked Brief Intervention are used in primary health care. Next, read sections 9 - 15 (pp. 19 - 36). This should provide you with a basic understanding of how to screen using the ASSIST and how to categorize a patient using an ASSIST Scorecard.