Install a copy of your distro of choice onto your computer and start using it. When questions arise you can:
A. Do a web search for the answers
B. Ask your question here or on a more specialised forum.
C. Download or buy a book/manual (many of them are free-as-in-beer).
Here's something to get you started:
http://puppylinux.org/main/tutorials...al-English.pdf
jdk