I'm going to be that person and correct this - Fire Force is Shounen Weekly Magazine (Kodansha), not Weekly Shounen Jump (Shueisha). 
As for how to get started in shounen manga fandom... I say just read as much as possible. Back in the day, we had to rely on scanlations to read manga. I would go around to various scanlation websites, download what I could, and read a lot. I learned about a lot of artists and their styles.
To get started nowadays, I recommend reading WSJ (Weekly Shounen Jump) via Viz at https://www.viz.com/shonenjump They publish the chapters the day they officially come out in Japan (mostly on Sundays but sometimes on Fridays. A few times a year it takes a week off) so you can always stay on top of what's new. I believe they do the chapters like the first 3 chapters and the most recent 3 chapters are free to read. It's something like $2/month to read the non-free chapters and AFAIK, it is available worldwide.
I also just want to say that Viz has some... questionable qualities though. Please keep in mind, that they have censored A LOT of manga in the past and are still doing it today (though from what I have seen it doesn't seem to be as bad as before. The most recent one was they just completely cut out a title page of Robo x Laserbeam because it was "racially sensitive" or something). Also, series where they use the graphic novel release will have really poorly translated SFX.
Sometimes, they straight out butcher manga with this extremely outdated, pointless, and hated practice. For some reason, they haven't stopped doing it AFAIK. In the magazine released chapters though, they don't do that! yay
But thanks to this, I was able to know about Kimetsu no Yaiba/Demon Slayer the day it came out since they published the first three chapters as they came out. yay