What do the numbers and letters on a breadboard mean?

[flyingpig]

Homework Statement

In our physics lab, we are doing E&M. We started using these things called "BreadBoard"

For some reason everyone but myself knows how to use them and I was really afraid to ask because it seemed like it is second nature to them. I looked into the lab manual, but it had no instructions for so ever.

Can someone just teach me how to use them? I know the top connects horizontally and the middle part vertically.

First of all, what do the letters and numbers mean? I saw my TA just connected the resistors randomly

 

[Kurdt]

There are plenty of online resources that you can find describing breadboards and how to use them.

for example: http://www.kpsec.freeuk.com/breadb.htm