I got all the way to step 143 and the "address" section never popped up. I couldn't add address as a filter. I tried to delete the entry and try again and now I can't enter the information without it showing as entry 3 instead of 2 and the other information for "Contact Info for Mountain View Reception" says it already exists so I can't re-enter any of that info.
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Ok, well you don't need to recreate "Contact Info for Mountain View Reception" you can just edit it to make any changes needed. So don't worry about that part.
And I wouldn't worry about the Meeting Attendance ID being 003 instead of 002. I'm sure your instructor wouldn't take off for that but if you really want to fix it, you can delete the 003 record you created and undelete the 002 record. (To undelete, just go to App Launcher, scroll to the bottom and find "Recycle Bin" and click it. Then find the record you want to undelete and use the drop-down menu on the far right of that row to select "Restore".
The missing Address part is your real issue and so that's what to focus on. My guess is that you didn't connect Meeting Attendance to the existing Contact object correctly. That was supposed to happen in Steps 83 to 85. So try deleting Address from Meeting Attendance first, and then delete Contact Name from Meeting Attendance and re-add it, carefully following those steps. Then try adding Address to Meeting Attendance again. If you have trouble, take a screencap so I can see what the problem is and post back, ok?