I love how each new Gravity Falls episode adds so much more context to the earlier ones. What might have seemed like an over reaction before has such a deeper meaning now. Stan really is a father figure to Soos and scenes like these show how just much he really cares about him.
So I was watching Boss Mabel and I kinda noticed the year on the book cover
is a year after Stan’s twin brother presumably got sucked into another dimension leaving Stan alone and desperate to save his brobro (with nothing but a bunch of notes and a broken multidimensional machine). Since then, he’s probably been doing everything possible to try to make ends meet and that’s when he bought the book hoping to start some kind of business. Like, he probably didn’t know shit about starting a business and he learned everything from that book (including having to wear shoulder pads lol).