I assume you're on a Mac, currently with macOS Sonoma (14.5).
You need:
git clone --recursive https://github.com/kleinmann/dotfiles.git ~/.dotfiles
cd ~/.dotfiles
brew install asdf
asdf install ruby 3.3.2
asdf global ruby 3.3.2
asdf shell ruby 3.3.2
gem install bundler
cd ~/.dotfiles
brew install gnupg
bundle
rake install
vim +PlugInstall +qall
brew tap Homebrew/bundle
cd ~/.dotfiles
brew bundle