These are historically separate characters, and they're meaningful, but it's relatively unlikely that you can use them as a way of learning Japanese or Chinese characters that you don't already know (as opposed to maybe as a way of helping to remember ones that you do know).

https://en.wikipedia.org/wiki/Radical_(Chinese_characters)

https://en.wikipedia.org/wiki/Chinese_character_classificati...

Also, in the Japanese case, they were borrowed from Chinese centuries ago and commonly given one pronunciation based on what the Chinese word sounded like to Japanese people at that time, and another based on the Japanese translation of the Chinese word.

https://en.wikipedia.org/wiki/Kanji#Readings

So yes, all of this is super-meaningful at an etymological level, but not transparent or reliable, and even trickier with Japanese rather than Chinese, because extra layers like kunyomi were added on top.

Many kanji are composed of symbols that are also kanji in themselves; there are also radicals which are not kanji in isolation but appear in the same form in many characters.

That being said, the meaning (or meanings...) of a kanji cannot be derived from its parts, just like the meaning of an English word cannot be derived from the letters that appear in it.

Also, as a rule, the same character will be read differently in different contexts. E.g. 生きる _i_kiru "to live", 生まれる _uma_reru "to be born", 学生 gaku_sei_ "student".