Max your 401K, roth IRA, and HSA. Buy the whole market via index funds - check out bogleheads https://www.bogleheads.org/wiki/Three-fund_portfolio . You should be able to do all that without making any adjustments from your previous job. Keep doing that for 20+ years and you'll be set at retirement, and probably be able to retire early.

If index funds aren't your thing and you like to gamble, then you could always pick stocks too... But if you are clueless the first option is the best, and you could always add single stocks as you learn.