DynamoDB Transaction Resolvers

[may215]

Hi,
I want to create DynamoDB Transaction Resolvers, where do I put them inside the project. I created several resolvers on aws and I call amplify pull and I don't see them.
Where do I need to put those file?
The extension of the files should be .vtl?
Does the name of the file correspond to the data source name I am using?

Regards