We'll use 4 of these 6 volt batteries, wired in seires/parallel to provide the juice we need at 12 volts.
To understand the series/parallel thing...look at the first picture of the 4 batteries -- you can see they are in two groups of two. If we take two 6-volt batteries, connect the positive terminal of one to the negative terminal of the other, we'll essentially have a 12-volt battery when a load is applied to the 2 remaining unused terminals. This is series wiring.
Now do the same thing to the other two 6-volt batteries -- you now have two 12-volt batteries. Wire the two unused positives, and the two unused negatives for a parallel connection -- just like the panels, it keeps the voltage the same, but increases amperage.
Never, by any means, connect the positive to the negative of the same battery. Always wear gloves, eye-protection and clothes you don't care about. Read books, talk to experts and get educated before fussing with big batteries!