I BEG of you: How do I replace an Airport Extreme base station with a 4th-generation Time Capsule as the base station?

Question

I'll be damned if I can figure this out.  I have a new late-2012 iMac (OS 10.8.3) connecting to my LAN via Airport wi-fi.  (It will be Ethernet-connected, as soon as a hole is drilled into my new work table, but right now the Ethernet cable doesn't reach.)  My wife uses a 2011 MacBook Air.
The LAN consists of a flying-saucer-looking Airport Extreme connected by Ethernet to the modem, plus 2 old Airport Expresses.  I have an Ethernet switch too, through which I've got a TV connected and a printer connected. 
I bought a 4th-generation Time Capsule about a year ago, but couldn't figure out for the life of me how to replace the Airport Extreme with it.  I became so incredibly frustrated that I hid it away in a closet until now.  I  just tried again, with the same results.  I've got both Airport Utility 5.6 (to use with the old Extreme and Expresses) and Airport Utility 6.2.  I was using version 6.2 to set up the Time Capsule... or to try to.  Once again, I cannot for the life of me figure out how to do it!  I tried so many different Ethernet wiring connections that I now cannot remember them well enough to describe them here.
I distinctly remember that, when I tried this a year ago with my wife's MacBook Air and Airport Utility 6.2, I was presented at one point with the question whether I wanted to replace an existing base station with the Time Capsule I was trying to set up, but this time I never was presented with that option.
Is there anyone who can, in essence, hold my hand and walk me through this process step-by-step?  At this point I even need to be instructed what to wire to what.  I feel like a total incompetent.
My MOST sincere thanks in advance for help!
(I hope Time Capsule is the correct forum for this question.  I considered the Airport forum as well, but I don't want to cross-post.)
(And, just to complicate matters, after I get this done-- assuming I ever do-- I want to use the old Airport Extreme on the outside of the house to extend the range of my LAN to the back yard... but that's for another day entirely.)

Answer 1

apikoros wrote:
The Utility transferred all of the AE's settings, so I still have to change the password, which leaves me with only 2 other questions, I think:
1)  I assume it's just a matter of using the Utility, entering a stronger password and checking for it to be remembered in Keychain Access.  But do I have to  change the password for each individual unit-- the TC, the Extreme and both Expresses-- or will changing it just for the TC alone work for the entire network?
Resetting the password you will need to do for each device... the utility cannot even see those old units.
So you will have to do it for each one.. think it through.. because as you change passwords the others will lose connection.. so start from the express which are wireless extending .. change those first.. and go back up the chain.. as each one changes it will drop off the network.. until you reach extreme and change that. Then you might need to reboot the whole network to get everything talking again. If something goes wrong.. just pluck that one out of the mix and plug in ethernet.. reset and redo the setup. That is my preferred method anyway.. do everything in isolation one by one. By ethernet and then nothing goes wrong.
2)  Who's the treasonous SOB who spilled the beans to you about the ICBM in my back yard?!?
N.Korean hackers.
[Edit] Whoops-- one more question:  I want to partition the TC's disk, but Disk Utility doesn't see it.  What do I need to do?
You cannot partition a network disk. And apple provided no tools for it in the TC itself. You can pull the disk out and partition it but that voids your warranty. (although done with care who is to know).
Look at Q3 here.
http://pondini.org/TM/Time_Capsule.html
Mixing TM and data on the TC is worth planning carefully. They don't necessarily sit happily together.