https://docs.aws.amazon.com/general/latest/gr/sigv4_signing.html - AWS documantation for Signing AWS Requests with Signature Version 4

Summary of Signing Steps

To make a signed request to AWS, complete the following:

1. Specify parameters for signature calculation in first node of the process:

required:

• HTTPRequestMethod - specify GET, PUT, POST, etc.
• CanonicalHeaders - consist of a list of all the HTTP headers that you are including with the signed request.
• kSecret - your secret access key from AWS account, section "Your Security Credentials".
• AccessKeyId - your secret access key ID from AWS account, section "Your Security Credentials".
• Region - specify the region that you are sending the request to.
• Service - the service you are requesting.

optional: (if some parameter is empty, use an empty string or empty object)

• CanonicalURI - the absolute path component of the URI, which is everything in the URI from the HTTP host to the question mark character ("?").
• CanonicalQueryString - the question mark character ("?") begins the query string parameters (if any).
• RequestBody - the body of the HTTP or HTTPS request.
• RequestDataTime - current data and time in the format YYYYMMDD'T'HHMMSS'Z'.

2. Specify Parameters (from the CanonicalQueryString and RequestBody from paragraph 1) and Headers (from the CanonicalHeaders from paragraph 1) for HTTP Request in the last node of the process.

Don't change the field Authorization.