Learning Pd and many other online open source tools requires you to get help by yourself. So at any time, you can right click (ctl+click on mac) on any object and get it’s help file. Read it.
You can also consult Pd’s documentation by going to the menu help/browser.
Finally, if none of these resources are enough, there is always a web search. In this web search you’ll find the archives of the Pd mailing list. You can join the list here.
You’ll notice there are many other resources for people to connect on pd matters, one of them is a very active facebook group.