Full disclaimer: seek financial guidance from a professional
That said, a good read is A Random Walk Down Wallstreet. Not too stuffy, very well regarded, and can arm you with some sound investing principles. (Principally, you can’t beat the market, primarily invest in large cap index funds)
Most 401ks now offer Target Retirement funds based on age groups. You could do way worse than those. I don’t use it in my plan, because I have solid S&P500 and bond funds available that I’m comfortable managing allocations to, but Target Funds are really easy, and quibbling over a percentage point here or there in potential returns is ignoring that your biggest hurdle in retirement savings is under funding your portfolio.
What are your current contributions getting invested in?