s3 cloudfront aws configuration

I already have an AWS account. I already set up Route53 and pointing the a name records to the cloudfront distributions, and the cloudfront distributions (subdomains) have the respective S3 buckets as origins. However I am getting access denied errors when accessing the website uploaded to the S3 bucket. I need someone to help me to properly configure those, total of 5 cloudfront distributions/S3 buckets. After this, I want to upload a full website and MySQL database, for which I need help and the correct configuration too.