Add docker support on VIM3l with debian buster Os (kernal 4.9)

Board : VIM3L
OS : Debian Buster
Kernel : 4.9

I am working on adding docker on vim3l using guide line Docker | Khadas Documentation

I got following error while installing docker

Reading package lists... Done
Building dependency tree       
Reading state information... Done
Package docker-ce is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source
E: Package 'docker-ce' has no installation candidate
E: Unable to locate package docker-ce-cli
E: Unable to locate package
E: Couldn't find any package by glob ''
E: Couldn't find any package by regex ''

It would be appreciated if pointers are given to move ahead.

Thanking you in anticipation.

@KD_1993 Please check the docker official documentation.