Welcome to the Cub family, and get ready to do alot of reading!
Read the info on the links provided here: http://www.farmallcub.com/phpBB2/viewtopic.php?t=1459
, and you'll find the answers to most of your questions and more.
Before you get to involved with fixin' and replacin' and repairin', pin down the year from the serial number. If the serial number plate is missing, you can get a good idea of the year from the casting codes on the major components like the engine block, torque tube, etc.
Rudi's website will allow you access to lots of manuals for the Cub and associated equipment, but the 3 most important ones are the service manual, operators manual and parts manual. You'll want hard copies of these, and can be ordered from Binder Books at http://www.binderbooks.com
. Of course, the ones you order depend on the year of your Cub.
You need to do some detective work to see how much of the electrical system was converted to 12 Volt.
Good luck and have fun with your Cub,