Just google for mutual funds. There used to be a video, but I think there is just an mp3 now at https://www.mytotalmoneymakeover.com...trl=daveramsey about what mutual funds are exactly.
Basically, you pool your money ("mutually") with a bunch of other people and the fund managers invest in whatever that fund's goals are, be it international or domestic funds, or a mix of both. They professionally manage all that money and sometimes takes a small fee for that service. I use Fidelity because we're set up with them at work and I've been pleased so far with their web site and ease of use.

If you're only going to invest for 6 months, stick to a money market or even a regular savings account (you can search online for higher yield savings accounts). The market is far too volatile to get tied up in a mutual fund for only 6 months, these things take years to develop into good investments as they roll up and down with the markets, but gradually grow over time.

If you do want to get into mutual funds though and don't know where to start, try calling one of the Endorsed Local Providers that you can find on the link above. I don't have any personal experience using ELPs but I trust Dave Ramsey as a pretty legit dude that would only link to people that were good folks who would sit down with you and actually teach you about what the investments entail.