Install manually or use a package manager:
" vim-plug
Plug 'beigebrucewayne/Turtles'
" NeoBundle
NeoBundle 'beigebrucewayne/Turtles'
" Vundle
Plugin 'beigebrucewayne/Turtles'
Copy color to vim...if ~/.vim/colors/
doesn't exist, create folder.
cp ~/.vim/bundle/Turtles/colors/turtles.vim ~/.vim/colors/turtles.vim
Inspiration