Should i not rinse my mouth with mouthwash after brushing? if not, when should i use mouthwash?

This isn't a health issue at all. Use it whenever you wish. It makes no difference.

Use mouthwash in a setting when you can't brush after eating a meal that contains garlic or onions or anything that can give you bad breath. Also on a date or when speaking in public.

If you don't clean teeth properly, and leave a layer of bacteria o teeth, the mouthwash never reaches the tooth enamel. To clean teeth properly you have to disrupt the dental plaque (mixed food debris & bacteria).65% of tooth gets cleaned with proper brushing, 35% with flsss. Maybe 1% with mouthwash. See your Den test for professional cleaning and personalized oral hygiene instructions.