My doctor prescribed me Flagyl and its a 4 pill treatment taken all at once do I need to take with a large meal?

Take with food. You will talerate this large dose better with food. Make sure you do not us any alcohol for about the next week. This medication and alcohol do not mix welll and can make you sick.
No. The recommendations are take under fasting, at least one hour before or two hours after meals.
No. Usually it's better to take Flagyl either 1 hour before or 2 hours after a meal. But such a large dose may cause stomach upset so eating something small when you take it should be ok.