Where do I start with investing? Should invest more in short term gains?

I’m 27. I have a money market solutions account and ROTH IRA currently. I honestly just dumped money in there and let it do its thing, however my initial goal with that account was for retirement. I’m finding that I have some shorter-term goals I’d like to invest for, such as buying land in 10-20 years-ish. How can I begin to learn about investing? I know the basics, like how compounding interest works, a few different account types, but I don’t have a deeper knowledge of investing. I have about $20k I’d like to park somewhere more ideal than my savings account to grow for awhile. I’ve heard HYSA aren’t necessarily the best since you’re paying taxes on gains and it barely outpaces inflation if it does at all. Treasury ETFs? SP500? Is it hard to learn to trade on your own? I will gladly take any all resources or ideas.