re: Gonna start as Pipefitter Helper with Turner on Monday. What exactly will I be doing

I did a lot of this during and after grad school.

You won’t be doing much.
You’ll probably help with setting up pipe where it needs to be. You might “fly it in” via chain and crane. Just watch your fingers.
You might use a grinder and maybe bevel some pipe?? Possibly more of a welder’s helper job.

Roll with the punches, learn to take a joke, laugh at the other guy’s jokes, and you’ll be ok. Learn to bitch about what they bitch about.
Don’t ever talk about your home life.