Keep the consonant on the left and ㅏ on the right. ㅇ and ㅎ are different letters. 아 and 하 are also read differently.
How to make the sound
Try each sound briefly. These are starting cues, not an automatic pronunciation judgement.
자 · 차 / 카 · 타 / 파 · 하
Work with two blocks at a time. ㅋ, ㅌ, ㅍ and ㅊ have a clearer puff of air at the start. Hold your palm a little away from your mouth to compare; airflow alone is not a full pronunciation test.