I did told you that ㅇ makes no sound BUT when its in the bottom it makes a NG sound;
Bang=방 you saw the placeholder in the bottom?

I already mentioned this two ㅣ&ㅡ
ㅣ makes an EE sound and ㅡ makes an EU sound

ㅏ this is A as in 'Ah' like the a in 'WHAT'

ㅓ this is EO it's like when you're saying 'O' but it's romanized as 'EO' also the eo in 'JEON'

ㅐ this is AE like the ay in 'WAY'

ㅔthis is E like the e in 'WET'

ㅗ this is O like the o in 'BRO' you can remember this symbol as a LINE ON THE TOP

ㅜ this is U like the oo in 'FOOD' you can remember this symbol as a LINE UNDERGROUND