人 already showed you one person, bowing forward. Stand a second person right behind the first, walking the very same direction, and three-thousand-year-old scribes had drawn 从: to follow. That single image of one figure trailing another grew into the ordinary Chinese word for "from" — because before you can say where something comes from, you first have to follow it back to its source.
A piece of culture
Confucius at seventy In the Analects, Confucius maps his own life in decades: at fifteen he set his heart on learning, at thirty he stood firm (立, which you already know), at forty he was free of doubts, and at seventy — his last stage — he could 从心所欲，不逾矩: "follow what the heart desires without overstepping the bounds." Look closely and you can already spot three characters you own in that line: 十 (ten), 立 (stand) and 心 (heart). Two and a half thousand years later, it is still quoted as the definition of hard-won wisdom: freedom that comes only after a lifetime of discipline.
Use it in a real word
从小
cóngxiǎo · cung4 siu2
since childhood — literally "from small"; you already know 小