How can i install docker from repository?

I am trying to install https://github.com/cupcakearmy/cryptgeon in my home server so that i can have privnote style website hosted on my home network in order to use it everywhere.

But i cannot figure how to set it right, i only know how to setup the ports, but other than that i am clueless, any help?

# docker-compose.yml

version: '3.7'

services:
  memcached:
    image: memcached:1-alpine
    entrypoint: memcached -m 128 # Limit to 128 MB Ram, customize at free will.

  app:
    image: cupcakearmy/cryptgeon:latest
    depends_on:
      - memcache
    ports:
      - 80:5000