Where you look depends on your printer. Models with an LCD screen show a short code, usually a letter followed by two digits, such as W-10 or E-02. Compact models without a screen communicate through the power and ink lights instead, blinking in a repeating pattern with a short pause between loops.
If you have a code, type it into the search bar exactly as it appears. If you only have blinking lights, count how many times each light flashes before the pause and describe it in the search bar, for example "blinking orange ink light" or "power and paper lights flashing together." Either way, selecting your printer model first keeps the match accurate, since the same light pattern can mean different things across Epson's printer lines.