Ive always felt that an easy way to both explain and remember "そう” is to compare it to one version or way in which we use the english "so"
Basically if you you have ever heard the star trek line "make it so", this matches exactly to "make it そう”
another example to illustrate my point:
"do so immediately"
The internet is surprisingly devoid of an accurate explanation of this, so let me try to break it down. First you need to know that "sou desu ne" (そうですね）is WEIRD to hear...it should be "sou desu nee" (そうですねえ）basically always.
You'll notice when I write Japanese in Romanji I put spaces in, which is important because the words don't always ...