Query from a docker noob

Hello All,
I am completely new to docker and i am not a developer. Right now i have an application which runs on centos/nginx/dotnetcore . In dotnet core i have 4 applications, we run them using dotnet appname.dll. If i want to dockerize this application, should i create centos as a separate image and then nginx as other image and then an image for each of the application ? If yes how do i link them, or should i create only one image with centos/nginx and all 4 applications (which is in tar) installed? Any help on this would be appreciated.