Help - just explain it to me like I'm a dummy 🤣

I got the AIPaper and I really like it so far! That said, the tip has worn down a ton in just the 24-ish hours since I got it!!! Is that normal? Or should I spring for the new ceramic tip???

Next: what are all the functions and why? What is the difference between learning, paper, picking, notes, etc? Why can't I find my documents once I import? I was writing on a note yesterday that I couldn't for the life of me find today, finally clicked all over the place and found it under "Paper" in a file folder, but not when I clicked on the Paper app!

I'm really considering returning it and getting a refurbished model and using the savings to buy the ceramic pen..... Thoughts?