
1sohs (1sohs) asked a question.
var roleArnToAssume = "arn:aws:iam::123456789012:role/testAssumeRole";
var principalArn = "arn:aws:iam::123456789012:saml-provider/testSamlProvider";
// Place your base64 encoded SAML response on this line with no whitespace
// https://docs.aws.amazon.com/IAM/latest/UserGuide/id_roles_providers_create_saml_relying-party.html
string base64SamlFile = "saml.xml.b64";
if (File.Exists(base64SamlFile))
{
string samlAssertion = File.ReadAllText(base64SamlFile);
var stsClient1 = new Amazon.SecurityToken.AmazonSecurityTokenServiceClient(new AnonymousAWSCredentials());
var assumeRoleReq = new AssumeRoleWithSAMLRequest();
assumeRoleReq.DurationSeconds = 3600;
assumeRoleReq.RoleArn = roleArnToAssume;
assumeRoleReq.PrincipalArn = principalArn;
assumeRoleReq.SAMLAssertion = samlAssertion;

Hi Peter,
Marian here from Okta support, I will assist you today with this inquiry.
If you are asked by the SP to provide the metadata file, the needed information can be acquired from the configured Template SAML App.
Steps to download or view the metadata file:
CAUTION - This information is dynamically generated. If you provide this metadata to your SP, you MUST use this template app to perform your integration. If the application will be modified after generating the metadata, it's recommended to download again the metadata file and updated on the SP side.
Thank you,
Marian Ungureanu
Technical Support Engineer
Okta Global Customer Care