ㄴ가 보이다

something shows, something becomes visible

Nearly every line here is the word 뭔가 "something" followed by 보이다 "be seen" or its causative 보여주다 "show". Two things are covered: something coming into view or clicking into place (you suddenly see what to do, learning an Asian language makes something open up, you keep seeing something in front of you that isn't there), and someone showing something to others (I thought you'd show me something, I'll show you something new). The -ㄴ가 is the suffix buried inside 뭔가 itself, not an ending you add separately — one line swaps in 어디선가 "somewhere" instead.