[docs] The installation guide is very bad

[saint777]

Is your feature request related to a problem? Please describe.
If you go to apollo.vuejs.org/guide-composable/setup.html you will see this setup example

import { createApp, provide, h } from 'vue'
import { DefaultApolloClient } from '@vue/apollo-composable'

const app = createApp({
  setup () {
    provide(DefaultApolloClient, apolloClient)
  },

  render: () => h(App),
})

the variable "apolloClient" just don't exist, how to create it?

Describe the solution you'd like
Need clear step by step guide for install process

Describe alternatives you've considered

1. Do this
2. Install this
3. Done
4. Example how to use ApolloVue

[yarotskiu]

Sorry, but this is a first row in the instruction: