Does we need to enable cloudtail ,vpc flow logs before enable Guardduty?

No – GuardDuty obtains the following datapoints/logs without ANY need to set it up:

• VPC Flow Logs

• CloudTrail

• DNS (VPC based)

https://www.youtube.com/watch?v=czsuZXQvD8E

Exact Time : https://youtu.be/czsuZXQvD8E?t=165