Help with some Terms

Newer to HUT, I haven’t played since ‘18 and didn’t get too into it then. I see a lot of terms that confuse me here. Could you help explain them with some depth?

MSPs, Fodder, 4x79?

I also was wondering, every guide I look up on how to earn pucks says working the market but none of them explain what that means. What’s that mean?

Thanks!!