22 - 65k base salary - 50k in loans, best options for saving

Hi guys, as my title reads I'm looking for some advice on PF.

I graduated from college in May and I have about 50k in student loan debt. I'm very fortunate as I landed a great job out of school with an expected gross of 80k including sign on and end of the year bonuses.

I'm looking for advice on how to save money while paying down loans and have some questions on best practices.

Should I contribute for 401k for the first year? Firm does not match for the first year, if I do, should I do it pre tax or Roth?

Expenses per month:

400 rent 250 car 215 parking 90 Smartlimk metro card 50 cell phone 20 gym membership 280 for student loans currently, others are deferred for a few months but I'd imagine it will increase to ~550 soon 200 food

I haven't worked long enough to figure out exactly how much I'll be taking home post taxes yet.

Advice on the best first steps considering my position?

Ty Ty!

I work in NYC if it matters