I watched tons of vim setup videos, for example this is last one and this person claims it takes 10 seconds to setup vim anywhere. He just opens vimrc file and it immediately installs all the plugins (time 9:09). When I open this vimrc file I just get bunch of errors, nothing gets installed. How do I make it work? What is the secret?
Unknown function: plug#begin error seems to indicate that vim-plug wasn't properly installed.
You can follow the instructions in here to install it:
In particular, you should have a file named
~/.vim/autoload/plug.vim in your system after you install it successfully. If you do have that file, then Vim should be able to find the
plug#begin function when it's called from your vimrc.