Tableau server doesn’t have this option by default in their website https://aws.amazon.com/quickstart/architecture/tableau-server/

 

 

Open their template file

https://aws-quickstart.s3.amazonaws.com/quickstart-tableau-server/templates/tableau-single-server-master.template

I wanted the Ubuntu instance. I could figure out that the Ubuntu Template exists here:
https://aws-quickstart.s3.amazonaws.com/quickstart-tableau-server/templates/tableau-single-server-ubuntu.template

 

Edit this file. Under “AWS::EC2::SecurityGroup”
Add Property “VpcId”: “vpc-xxxxxx”

Under “AWS::EC2::Instance”

Add Property  “SubnetId”: “subnet-xxxxx”