Welcome!
The first step is education and one of the best places to start is to read Floyd Toole's "Sound Reproduction" 3rd edition, assuming you're planning on doing in-room listening. It's the consummate audiophile primer for learning how speakers and subwoofers behave in-room. Every residentially sized room has huge bass peaks and dips which are best addressed via multiple carefully placed subwoofers. And you'll learn what a good listening room consists of (bigger the better but shape is very important too - avoid square/cubic rooms). Plus sonic isolation is paramount. Having a dedicated room is also highly desirable so you can listen when you want and maintain proper setup. So if possible develop a listening room.
The next step in your education is to determine what sonic attributes you value. Realize that pin-point imaging is the whole point behind stereo, but other factors (such as avoiding one note bass, good dynamics, flat frequency response, sharp detail, and life like treble) should also be figured in. Then it's time to go speaker shopping. Start with speakers because they make the biggest difference. For most of us, especially those of us living far from brick and mortar audio shops, that's going to start with internet research. With enough reading you'll find reviewers (professional and otherwise) that you develop a like mindedness view point. You'll also find that there are a variety of basic speaker designs.
Typical speaker types: monopole (traditional); dipole (also includes open baffle); bipole (speakers on front and back); omnipole (typically up firing cone drivers); horn loaded (in front or behind the driver(s)); and vertical array (using multiples of the same drivers). Most audiophile speakers are passive (meaning that they need a power amp), but studio professionals almost universally use active monopole speakers (usually monitors that sit on the recording console). If you're thinking about a combo audio and home theater system realize that nearly all use passive monopoles.
Next plan a trip to audition speakers. Take a wide variety of your favorite music and take notes. Don't let the sales staff skimp on the time/setup as you'll be auditioning the shop/sales staff too. Limit yourself to 3 or 4 speakers per day to avoid listener fatigue. This could take the better part of a day. And don't stop at just one shop. The wise hunter is careful and takes his time. After speakers (if passive) find the amp that serves them best within your budget.
Then it's time to decide on source for prerecorded music. The cheapest and most convenient is to stream from the internet. Tidal, Qobuz, and Amazon HD are CD quality streaming services that cost $20/month or less and offer access to millions of albums. If you don't want to hassle with computers, software, and DAC's (Digital Analog Converters) you can still find CD's (relatively cheap) and good quality CD players. Vinyl is the other popular option, but sourcing is expensive and a crap shoot. Turntables can be mega expensive but definitely provide more of a hands-on hobbyist experience.
