Here are phonetic explanations of each sound.
ㅂ the unaspirated bilabial plosive
ㅍ the aspirated bilabial plosive
ㅃ the bilabial plosive with tense phonation
ㄷ the unaspirated alveolar plosive
ㅌ the aspirated alveolar plosive
ㄸ the alveolar plosive with tense phonation
ㄱ the unaspirated velar plosive
ㅋ the aspirated velar plosive
ㄲ the velar plosive with tense phonation
A bilabial consonant is a consonant articulated with both lips.
An alveolar consonant is a consonant articulated with the tongue against or close to the superior alveolar ridge, which is called that because it contains the alveoli (the sockets) of the superior teeth.
A velar consonant is a consonant articulated with the back part of the tongue (the dorsum) against the soft palate, the back part of the roof of the mouth (known also as the velum).
A plosive(stop) consonant is a consontant in which the vocal tract is blocked so that all airflow ceases.
In phonetics, aspiration is the strong burst of air that accompanies either the release or, in the case of preaspiration, the closure of some obstruents. In English, aspirated consonants are allophones in complementary distribution with their unaspirated counterparts, but in some other languages, notably most Indian and East Asian Languages, the difference is contrastive.