@chinchilla Repeating the advice for you to invest in index funds with low fees (low expense ratios, no hidden fees). Vanguard was one of the earliest companies to offer low cost index funds which is why they are often suggested. Fidelity and Schwab also offer similar low fee products.
Don't invest money you plan to use in the next 3 to 5 years. Expect the stock market to go up and down and don't pay any attention to it.
As to what specifically to invest in, check out the funds listed on the bogleheads wiki for three fund portfolios (https://www.bogleheads.org/wiki/Three-fund_portfolio) or lazy portfolios (https://www.bogleheads.org/wiki/Lazy_portfolios).
You'll see on the lazy portfolio wiki that VTI and VTSAX are both "Total US Stock Market" funds. VTI is the ETF version and VTSAX is the mutual fund version. They are the same thing. Vanguard has a FAQ of the difference between their ETFs and mutual funds (https://investor.vanguard.com/investor-resources-education/etfs/etf-vs-mutual-fund) Once you have at least $3k invested then you can set up automatic contributions to mutual funds. If you don't have $3k to invest yet then you'll need to start with an ETF.
Whichever funds you choose, be sure to check back a few days after you buy them to make sure that the money is not sitting in a settlement fund. You want to make sure that it gets invested in the fund(s) you chose and is not sitting around in cash doing nothing. With the Vanguard website I think it's fairly straightforward to avoid this mistake, but that is something to be aware of and has happened to people. You don't want to find out years down the road that your money hasn't actually been invested.
Don't invest money you plan to use in the next 3 to 5 years. Expect the stock market to go up and down and don't pay any attention to it.
As to what specifically to invest in, check out the funds listed on the bogleheads wiki for three fund portfolios (https://www.bogleheads.org/wiki/Three-fund_portfolio) or lazy portfolios (https://www.bogleheads.org/wiki/Lazy_portfolios).
You'll see on the lazy portfolio wiki that VTI and VTSAX are both "Total US Stock Market" funds. VTI is the ETF version and VTSAX is the mutual fund version. They are the same thing. Vanguard has a FAQ of the difference between their ETFs and mutual funds (https://investor.vanguard.com/investor-resources-education/etfs/etf-vs-mutual-fund) Once you have at least $3k invested then you can set up automatic contributions to mutual funds. If you don't have $3k to invest yet then you'll need to start with an ETF.
Whichever funds you choose, be sure to check back a few days after you buy them to make sure that the money is not sitting in a settlement fund. You want to make sure that it gets invested in the fund(s) you chose and is not sitting around in cash doing nothing. With the Vanguard website I think it's fairly straightforward to avoid this mistake, but that is something to be aware of and has happened to people. You don't want to find out years down the road that your money hasn't actually been invested.