You can switch tty as you have described by pressing:
- Ctrl + Alt + F1 : (tty1 x is here on ubuntu 18.04+)
- Ctrl + Alt + F2 : (tty2)
- Ctrl + Alt + F3 : (tty3)
- Ctrl + Alt + F4 : (tty4)
- Ctrl + Alt + F5 : (tty5)
- Ctrl + Alt + F6 : (tty6)
- Ctrl + Alt + F7 : (tty7 x is here when using ubuntu 14/16)