Depends on where you live. If in the US then Studio 5000 would be a better programming software to learn in terms of what’s commonly used here. If Europe TIA would likely be the most used. More on reddit.com

Don’t really know, I would go step to step. Analog: this depends on the Card you get the values from. 0 and the highest number is mostly declared for errors, so like sensor wire broken (0) or a short of the cable (high). There is a good explanation in the docs of the analog input modules. There are the two blocks scale and norm, they come in handy if you use Siemens hardware for analog modules. Besides this: it’s a good idea to avoid Merkers, have knowledge of the docs from Siemens like „programming guideline“ and the „styleguide“, they are a good start! The rest depends on what people is your course designed for. Don’t read /write to IO addresses you don’t know. Like please declare all addresses you use in the plc mapping. Some asshats here used hardware devices via profinet and used only the addresses indirectly, so it’s hard to find their stuff because it’s not additionally declined in the plc mapping. Have fun searching for references… If you want you can also go over the errorhandling OBs declared in TIA. Like the OBs for hardware fault, programming fault and the like. IMHO is the rest learned when the specific problem arises :-) Oh and for basic stuff: how the IO communication works. I mean that the input/output process image is now consistent on the 1200 and 1500 series with profinet. More on reddit.com

Hegamurl the GOAT. I am mostly self-taught and would not have gotten anywhere in TIA Portal without this man's fantastic content. More on reddit.com

Yes you can learn it without hardware. I'm still learning new stuff all the time. The manual is a 20,000 page pdf. More on reddit.com