Maybe the best introduction is to check out the Wikis on Shortwave, whether here or at Wikipedia.
There are some SW sites like The SWLing Post that have a lot of information on various aspects of the hobby.
Overall, it's tough to learn a lot by doing right now because propagation is so poor. The best thing to do is to check the bands -- if you're into ham bands, 40 meters (day or night, although night is best), 80 meters (at night) and 20 meters (afternoon and daytime) are probably best, and if you're into SW broadcasts, the 49 meter band at night and 31 meter band during the evening are probably the best bets for hearing stuff.
When conditions improve in a couple years, the other bands (15 meter ham band, 10 meter ham band, 19 meter SW broadcast band, 17 meter SW broadcast band, etc.) will open up.
As for LSB and USB, it's 'sideband', which is a form of transmission that gets a signal out farther per watt. Hams use it mainly (along with a few other services), but on the 40 meter and 80 meter ham bands you will hear LSB, and 20 meters and higher the hams use USB. If you want to listen to the morse code sections of the ham bands (usually the lowest section of each band), either LSB or USB will decode it.
I'm not sure I understand meter bands correctly. Are they chunks of the 0-30,000 mHz spectrum? Like, I listen to both my radio and SDRs people have kindly put up on SDR.hu. Most of them have a range of 0-30,000 mHZ, with dropdown options for different bands. I just assumed those options just took you to different ranges within the big range of 0-30,000 (in the common case). Is that not right?
The SW spectrum is divided up into 'bands' by use. Yes, they are specific ranges within the 3-30 Mhz SW spectrum. There are ham radio 'bands' and SW broadcast 'bands', as well as other parts of the spectrum (which you may or may not call 'bands') used for military, aeronautical, marine, etc.
The ham 'bands' and the SW broadcast 'bands' are swaths of HF spectrum about as wide as the MW broadcast band. They usually are referred to as "meter bands", it's a leftover practice from the 1920's when radio people used wavelengths, in meters, to describe where they were on the dial, instead of the frequency.
The 49 meter band I mentioned is from roughly 5800-6300 khz.
The 31 meter band I mentioned is from roughly 9200-10000 khz.
The 41 meter SW broadcast band I referred to is from roughly 7200-7400 khz, although there are some stations overseas that broadcast as low as 7100 khz. Right below that band is the 40 meter ham band, where the hams talk, send digital signals, and morse code. The 40 meter ham band is from 7000-7200 khz (there is some overlap, obviously).
The 20 meter ham band (the most popular one) is from 14000-14350 khz. The lowest section is where morse code happens. Higher up, you'll hear digital signals and then Sideband (USB).
I hope this helps. I know it's a bit confusing to a newcomer, and it's not always the easiest to explain.
EDITED a typo: 40 meter ham band is 7000-7200 khz (roughly, depending on country and type of ham transmission) not 7000-2200 khz.