Hi @VictorioBerra ,
It’s a little difficult to present you a full example, here.
In general you need an Identity Pool and use that to log your user in using the SDK. If you also use a User Pool as an authentication provider and want to invoke your APIGW through JS, later, you may find “Use Case 17” here useful.
Once you managed to log users in, you furthermore need to generate an SDK for your APIGW and invoke the endpoints through it. You may find this useful: Invoke API Gateway function with Cognito Authentication from Javascript
Note: the “cognitoIdentityId” will be the “user’s” ID in the Identity Pool; not the User Pool.