what does discovery mean in a civil lawsuit.?

I have a harassment lawsuit against my employer and it was recently dismissed because of a filing error on my part. Now the clerk of court has sent me a letter asking me and the opposing attorneys to present discovery to each other. I'm representing myself and the attorneys for them really jerked me around. The amount I'm asking for is miniscule and lawyers are asking more than that to represent me. Anyway, does anyone know of free online advice to help me? At one point I really wanted to drag my employer through the mud. Now, I just wants this thing to be over. By the way, I'm still employed there.