The purpose of using the heat gun is to reheat the adhesive for easy removal. Plug in the heat gun and ensure it will reach your work area. You may need to use an extension cord. Direct the heat gun toward the adhesive. Place the heat gun as close to the adhesive as possible without touching it. Continue until you see the adhesive begin to give and melt. Use an old, but clean, towel to begin to wipe away the melted adhesive. You may want to re-heat the adhesive and wipe again. Carefully move your floor scraper over the surface of any remaining adhesive. Move gently enough to avoid damaging your floor.

Summary:
Locate a heat gun. Apply heat to the adhesive. Wipe the area with a dry towel. Use a scraper to lift any leftover residue.