I'm not sure how i managed to get so far in my life with out knowing where a basic full stop should go

So for people that don't know me, I am terrible at punctuation and spelling. Not that kind of bad that is just forgetting every so often, but that kind of bad that leads me to think "I'm not sure how i managed to get so far in my life with out knowing where a basic full stop should go". I did Primary, Secondary and multiple colleges and still i am apparently at a basic primary school level.

This has been my main avenue of focus for a while and most of it goes in one ear and out the other but i think im going to try bit by bit. So my first is the semi colon; it is used when the second statement is along the same lines as the first statement but the first statement in itself could be a complete sentence.

So im opening this up does any one have any other reasons for using it?

I'm sure there will be more punctuation based blogs so get swatting!