I would suggest if you want to become an PSADMIN, best way to start is to download the software. After Oracle taking over PeopleSoft, everything is available for download as long as you do not use it for commercial purpose,which you might already know. Refer to Oracle’s License agreement while you download.
I have provided the links on where to download the software from OS [Oracle RHEL] to PeopleSoft,
documentation page and the license keys for the software. Make sure to have a system with good configuration.
Once you are able to install the entire PIA from OS, to Oracle DB, People Tools and Other layers of PIA and make it working, then you have got some idea about the PSAMIN knowledge that are required to start with.
If you come across any issue feel free to post your issues here, will try to help you install. Also refer to the People Books which contains answers to most of the questions.
If you want to receive email alerts for your questions if some one response to the questions you posted in here, you need to register yourself at psadmin.org.
Then later, start learning other areas of PSADMIN tasks.
Also suggest you to read the other discussion
here., which gives some details about the responsibilities and admin’s daily tasks. As you have worked in PeopleSoft environment, it should not be difficult for you.
Best of Luck.