How do I apply the texture paint to a specific object? I am new to Blender and I am using Blender 2.8. I want the texture paint that I created to apply only to the character's jacket but it's applying to the entire body. How do I fix that?
Go into edit mode. Select the polygons that you want a different material on. Go to the Material tab. Click (+) to add a new Material slot. Choose a material  or create a new one and then click "Assign".