R, I would strongly recommend you visit (and join) the Bogleheads.org website. It is a great source of excellent information.
If I were starting over today I'd look to keep it simple and well balanced which you can achieve with just a few low cost index funds in either taxable, Roth or traditional IRA accounts. A total market domestic fund, a total market international fund and a domestic or global bond fund is really all you need.
The ratios of equities to fixed income will vary according to the time frame you intend to invest the money and your ability, willingness and
need to take additional risk.
I would recommend a very basic book by John Bogle called
The Little Book of Common Sense Investing. There is much wisdom in this little, easy to digest volume and it's a good place to start.
I like the Vanguard Funds but there are other worthy fund families as well.
ETA:
Pangloss mentioned Bill Bernstein and he is right up there in the pantheon of investing greats whose work I enjoy. I have corresponded with Bill many times over the years. He can be a bit complex in some areas but he also has some very simple "platitudes" which make a great deal of sense.
I also enjoy the work of Larry Swedroe quite a bit and of course, Mr. Bogle, as mentioned above.
Look into making an "Investment Policy Statement" for yourself. It can be simple enough to write on a cocktail napkin but it will give you a basis for steering your investments (only) as required over the coming years.