Do you mean what is 받침? 받침 is just the final consonant of a syllable block. It's always on the bottom, centered under the letters above it. 받침 has to be a consonant. 참 -> there is 받침. The 받침 here is ㅁ. 무 -> there is no 받침 사촌 -> the first syllable has no 받침. The second syllable does have 받침. The 받침 in the second syllable is ㄴ. Whether there is 받침 or not can affect the particle after the word. For words with 받침, there is sometimes an alternative version of a particle. This alternative version is ㅇ+a vowel (like 으). There is an alternative version for some particles when a word ends in 받침 to make the pronunciation easier. This is the same concept as "a" and "an" in English. The only thing that matters for knowing which particle to use, though, is the final syllable and whether there is 받침 in that syllable or not. It mostly does not matter which consonant is the 받침. It mostly only matters whether or not there is 받침. The only time it can matter is if the 받침 is ㄹ. Again, this has to do with ease of pronunciation. Examples: 사과 -> no 받침 -> use 가, 로, 예요 고양이 -> no 받침 -> use 가, 로, 예요 변기 -> no 받침 -> use 가, 로, 예요 노트북 -> 받침 (ㄱ) -> use 이, 으로, 이에요 문 -> 받침 (ㄴ) -> use 이, 으로, 이에요 손 -> 받침 (ㄴ) -> use 이, 으로, 이에요 선물 -> 받침 (ㄴ, /ㄹ/) -> use 이, 로, 이에요

If I understood your question right, there is a good explaination about it here, at least that is what I followed to learn it. http://www.koreanwikiproject.com/wiki/Hangeul_step_5 The examples help a lot, in my opinion, but I agree that the way the letters change sound depending on the position can be confusing.

"Thank you! This, I understand. I'm confused about how to tell the way it should be pronounced, for example ㅎ and ㅅ being pronounced as with a "T" sound if it were on the bottom. How do you know when to pronounce it this way? Sorry if this doesn't make sense!!" You know when to pronounce it this way...when it's on the bottom! Haha^^ Unless there's a letter after it that has an aspirated version (ㄱ, ㄷ, ㅂ, ㅅ, ㅈ) or ㅇ (no sound). The letters only make their 받침 sound when they're functioning as 받침. If it's in the initial position, it will sound different.

Here's the resources I like to share: https://en.wikibooks.org/wiki/Korean/Essential_Pronunciation_Rules https://en.wikibooks.org/wiki/Korean/Advanced_Pronunciation_Rules Personally, I don't find it confusing. It's just natural sound changes. It's completely logical and normal. There's really only a few to maybe think about. The rest are simple. It follows a clear pattern. And the letters make a lot fewer sounds on the bottom. Just practice listening and speaking. You can also check out the pronunciation of a word here: http://dic.naver.com/