Plain consonants you meet on signs

ㄱ g/k, ㄴ n, ㄷ d/t, ㄹ r/l, ㅁ m, ㅂ b/p, ㅅ s, ㅇ silent at the start / ng at the end, ㅈ j.

ㅇ is the empty seat. 아 is just ㅏ wearing a placeholder. Without ㅇ, a vowel cannot sit in a block.

Read 김치, 라면, 비빔밥 as blocks: 김/치, 라/면, 비/빔/밥. You already know the food. Now you can read the ticket.