One thing that I see confuse more new podcasters is RSS and syndication.
Let's say you are a radio station and your frequency is 100.7. You could have Panasonic, RCA, Sony, JVC all tuned to your station. When you play a song it comes out of all the radios as they are tuned to your station.
With podcasting, instead of a frequency, you have an RSS feed. Instead of radios, you have apps (Apple and Google Podcasts, Stitcher, TuneIn). So when you put out a new episode it goes to those apps. You then create a post on your website as well to attract Google so hopefully, you come up when someone searches for your topic.
You do not upload anything to Apple or the other apps. They are all mirrors of whatever is in your feed. Most media hosts provide an apple compliant feed. There are also WordPress plugins like PowerPress. No matter what you use for your feed, make sure you can redirect your feed (so if you ever want to leave your current situation you can take your audience with you.
You submit your show to these directories once, and once accepted they “tune in” to your feed and never tune out. You just keep making episodes and they appear in those apps. Apple is somewhat special as there are two versions. A web-based version I call your Apple listing, and the app/software versions iTunes and Apple podcasts. With Apple iTunes/podcasts any changes you make appear almost instantly to anyone who subscribes to your show using those apps. However, the Apple listing is more of a snapshot in time that is updated every 24 hours.
With this in mind, you could be looking at Apple iTunes desktop software and not see the episode you released two hours ago. Then subscribe to your show and see the episode. Why? Because the listing only updates every 24 hours (or less).
One thing I recommend to all my clients is to subscribe to your own show. This way when you see the episode appear on your device, you know Apple or other apps just need to catch up. Technically speaking your podcast is fine.
One last thing about RSS feeds. Once you are accepted into the directories you can change the location of your feed. If you change to a new website address, you need to take care to redirect the old feed to look at the new address. If you are using Libsyn.com you wouldn't want to change your slug. In both of these situations, it's like (going back to the radio analogy) moving our station from 100.7 to 98.5 and not telling any of your listeners. You are (more or less) blowing up your show and starting from scratch.
If you have any questions, I realize this is one of the more confusing items in podcasting so don't hesitate to contact me