Welcome, pcl! I hope that you've been warned that this place is addictive and there is NO cure! ..... LOL!
You are not the only one having trouble understanding bump lists ..... a lot of us "oldies" are confused about it, too. I'll tell you what little I know and maybe someone else will come along and fill in more details.
For starters, bookmark (on your hard drive ... in my browser that means adding it to my favorites) this URL:
Free Republic Bump List Register
You can then go to that site to find all the topics for which there is a bump list. Click on the topic you're interested in and all the FR threads on that topic will be listed.
Is that confusing enough for you?