Need help to create a DockerFile

Expected behavior

I glone this web app that contains node.js and react and its dependencies. Now, I need to dockerize it in a docker container. However, I am not sure if I should create a dockerfile first, since I already have the json.package listed there. If I have to create one, is there anyway for the npm to pull all the depencies base on the json.package before building the image. I also need to copy the git clone to a specific directory like copy NamedWebapp/abc /abc like that and I would like to know how to make that happen. Or do I have to create the Dockerfile manually which I have read it in the Docker tutorial somewhere…

Actual behavior

Additional Information

I am using Putty to do the CI CD to AWS ec2 instance.
Therefore, I am not not sure if I need to use pscp to do the copying to the specific directory abc. Or when I specify it in the dockerfile, this directory will be created automatically when I run docker build -t NamedWebapp

Steps to reproduce the behavior