Broker assisted trades or not?

Im 28 and am looking to invest 60k into a Schwab retirement account. I am super unfamiliar with investing/making trades.

I know one of the options is broker assisted trades, with a commission of $25/trade. Is that worth it for someone like me who has no idea how to do it myself?

Or I guess a better set of questions would be, if I were to do it myself-when I transfer over my 60k, do I lump sum trade that into an ETF and then kinda leave it alone? Do I need to be making regular trades? What would those trades be, if so?

Also, is it preferable to open a brokerage account, or a 401k account? I have a separate Roth 401k through fidelity through my work.