“How do I even start?”

Smaller than you'd think. You don't need a strategy on day one — you need three things, in order.

First: log into your plan portal (or ask HR how) and confirm you're actually enrolled and contributing something. Some plans auto-enroll at a low default rate; some don't enroll you at all until you act.

Second: find your match formula and set your contribution rate to at least capture all of it. This is the single highest-leverage move available to almost anyone.

Third: notice what your money is invested in — plans often default to something reasonable (a target-date fund), which means "I haven't decided" and "I'm invested sensibly" can quietly be the same thing, but it's worth confirming rather than assuming.

That's genuinely the whole starting move. Everything else — how much to increase later, Roth versus traditional, what to do with old accounts — is a real conversation, not a checklist item, and there's no rush to have it alone.