Online resources to read and use
The US Government (Securities and Exchange Commission) has an entire website dedicated to learning about investing from the ground up in the United States: https://www.investor.gov/introduction-investing
Investopedia is a great go-to resource if you don't know the definition of a term. They also have a litany of educational resources, but they vary in quality and might leave you wanting more information.
As much as I dislike reddit, the Personal Finance board on reddit is an excellent place to read up on things you've heard mentioned in the past but didn't quite know what they meant. Their wiki (linked) is a treasure trove of knowledge, but always be careful to check that it isn't dated. General financial information usually stands the test of time, but you never know.
Stay abreast of things happening in the world around you. I recommend reading Hacker News to get a view on some companies that are on the upswing, especially tech companies that are looking to make what's called their IPO: Initial Public Offering, where they list themselves on the stock exchange and make stock in the company available for public purchase.
Going back to reddit, their Investing board also has a substantial wiki that you'll want to spend time reading. Huge treasure trove of information, going through it myself.
I also recommend the Personal Finance Circlejerk board, believe it or not. For the techies reading this, if you've ever read the reddit board Programming Circlejerk, it's the same concept but for their personal finance board. For the uninitiated, it's the users of the personal finance board making satirical posts based off of actual content they've seen on the parent board. The reason I recommend it is because you can start to develop a barometer of what posts on the personal finance board are well-intentioned memes that you shouldn't actually follow through with and what sounds crazy but actually applies to you.
I also get a lot of information from J.P. Morgan Chase. They have a lot of articles on various facets of investing and finance as well as a market insights newsletter they periodically send out to free subscribers. Most of the information I've been processing and posting here does come from these posts but they also have posts with overlap or entirely duplicate posts, so part of the process is centralizing that info.
You don't have to really read any of these like a bible (possible exceptions include the wikis, JPMC, and the SEC's investing website), but you'll want to check in on them every so often. I check in with Hacker News daily as part of keeping up with my industry and keeping an ear to the ground in regards to financial events and sentiments. Magazines like Financial Times will make a lot more sense and have way more appeal once you get into this.