AWS Gamelift Windows Access With SDK 5 or Above

Question

I'm trying to connect AWS Gamelift Windows 2016 instance from my local. Procedure was simple describe-instances, get-instance-access, update-fleet-port-settings, rdp and go.
BUT :
Amazon made an update on Gamelift 5.0 or above sdk's no longer use get-instance-access. It says to use get-compute-access instead. This is written only in CLI and Amazon documents have nothing about this.
BUT :
get-compute-access doesnt provide any kind of username or secret key to access instance. Instead it provides, temporary AccessKeyID, SecretAccessKey, SessionToken. I have checked their documentation here. What I see here is it gives credentials of gamelift s3.
BUT :
When I tried to connect it via WinSCP, selected protocol as s3 placed accesskeyid, secretaccesskey, sessiontoken ( session token is in the advanced tab only), it gives me access denied.
I couldnt find good documentary for it, could you please forward me some stuff to solve this ?