In Emacs-land, C is the Control (or Command) key and M is the Alt (or Options) key. C-x means “Hold Ctrl and press x”, C-c C-o means “Hold Ctrl and press x, then o”, and M-o a means “Hold Alt and press o, then release Alt and press a~.
In Emacs-land, C is the Control (or Command) key and M is the Alt (or Options) key. C-x means “Hold Ctrl and press x”, C-c C-o means “Hold Ctrl and press x, then o”, and M-o a means “Hold Alt and press o, then release Alt and press a~.