Just think - the English alphabet is only 26 letters. However, the alphabet doesn't include all of the sounds in English, dipthongs, etc. Remember how you learned the alphabet when you were little? But then you spent all that time practicing short and long vowels and letter combinations (ex. "th" and "tion") and so on and so forth. Well in Korean the basic alphabet just represents those simple sounds too. However, they also have characters representing the rest of the sounds possibly made in Korean that are compound or double letters. ㅘ isn't anything crazy. If say ㅗ ㅏ really fast together they blend and make the ㅘ sound. It's easy - just a compound vowel.

There are 24 letters in the basic Korean alphabet, but there are 40 letters in total. These last 16 letters include the five double consonants ㄲ, ㄸ, ㅃ, ㅆ, & ㅉ and 11 compound vowels (ㅐ,ㅒ,ㅔ,ㅖ,ㅘ,ㅙ,ㅚ,ㅝ,ㅞ,ㅟ,ㅢ). ALPHABET: ㄱㄴㄷㄹㅁㅂㅅㅇㅈㅊㅋㅌㅍㅎ ㅏㅑㅓㅕㅗㅛㅜㅠㅡㅣ. ALL LETTERS: ㄱㄴㄷㄹㅁㅂㅅㅇㅈㅊㅋㅌㅍㅎㄲㄸㅃㅆㅉ ㅏㅐㅑㅒㅓㅔㅕㅖㅗㅘㅙㅚㅛㅜㅝㅞㅟㅠㅡㅣㅢ

hangul like the first one here: ㄲ or ㅉ,ㅃ, etc. I've already learned all the basic ones I think though

The two vids that really helped me with hungul where learning korean with professor Oh vids and Talk to me In Korean vids. They both break down Hungul and make them easy to memorize.

It is difficult to know what you hangul characters you are talking about. Are you asking about specific words or letters/clusters?