I was like Naimi, with the back labour! I had dreadful back pain for 2-3 days before having my little one, I knew she was on the way as I couldn't stop sleeping and had to be in the fetal position as anything else would hurt too much. I had no pain in my front (if I did, it isn't memorable so can't have been that bad).
The best way to explain would be waves or ripples of pain which intensify as they move up. My pain was lower back and would start slowly, then build up and id feel a greater pressure on my back (just imagine waves on the sand

)
Id imagine the pains in the front would feel very similar, but probably more like a really really intense period pain to start with. You can get a lot of braxton hicks near the end so don't worry, im sure you'll know when it's time. Braxton hicks feel like tightening, hard stomach and are often a little painful near the end of pregnancy.
Hope I haven't scared you with this, wanted to explain as well as possible.
