How to start a Docker container that has already been created and go into the shell to manipulate it

Some students have installed nginx under Docker but do not know where the directory is, you can use the command

" 50x.html "

Because Nginx is bound to have 50x.html, so look for it, the results found Nginx directory in the Docker container, if you operate it, you need to enter the container shell.

The container must be started first

sudo docker start "Container ID"

Then use the command below to enter the shell

sudo docker exec  -it "Container ID" bash

How to start a Docker container that has already been created and go into the shell to manipulate it