There is a preinstalled on-screen keyboard app in your TV which will appear whenever text is expected to be entered by the user, e.g. Wi-Fi password or website address in the web browser. To navigate the on-screen keyboard, use the ARROW buttons on the remote control, enter the character selected by pressing OK.
If you press and hold the OK button for 2 seconds while on a selected symbol, this will display the associated national character(s) with accents or diacritical marks.