If you want to copy everything from a S3 bucket to the current directory, you can use the following command
C:\temp> aws s3 cp s3://bucketname/ . --include "*" --recursive
This assumes that you have already installed and configured the the AWS CLI tools.
To install the tools, do a search for “AWS CLI tools”.
To configure them, use
C:\> aws configure
You will need to know have setup an IAM account and need to know the Access key ID and the Secret access key for the account and the region code for your account. Note that the region you specify when running configure probably isn’t what you see it the top right corner of the AWS console. See the list of regions and their code here : http://docs.aws.amazon.com/general/latest/gr/rande.html