How to switch to a different buffer from a terminal buffer
Solution 1:
In term-mode, any regular C-x whatever keybinding becomes C-c whatever instead.
Solution 2:
I'm not sure I understand your question. If you run M-x terminal, most of the key events are sent to the underlying terminal, so the standard C-x o binding and your M-Left are not available in the terminal.
Try using M-x shell to get a shell in one of the windows, and the navigation bindings you set up should still work.