How do I install fzf.vim using Vim 8 native package loading?

- [x] I have read through https://github.com/junegunn/fzf.vim/blob/master/README.md
- [x] I have read through https://github.com/junegunn/fzf/blob/master/README-VIM.md
- [x] I have read through the manual page of fzf (`man fzf`)
- [x] I have searched through the existing issues

I'm using native vim packages on Vim 8.1

When I do the following:
1. Add the fzf binary to `rtp` in my `.vimrc`
2. call `fzf#install()` in my `.vimrc`

I get the following error:
```
Not an editor command: fzf#install()
```

So far all of the documentation related to installation has to do with Vim Plug. How do I install fzf.vim using Vim 8 packages?