I suggest you to use AWS CLI. As it is very easy using command line and awscli
aws s3 cp SOURCE_DIR s3://DEST_BUCKET/ --recursive
or you can use sync by
aws s3 sync SOURCE_DIR s3://DEST_BUCKET/
Remember that you have to install aws cli and configure it by using your Access Key ID and Secrect Access Key ID
pip install --upgrade --user awscli
aws configure