Question about merging

With the constant flurry of warnings stating "If you want to merge chapters 1 and 2, you have to do it at the start or else you will never be able to go back if you change your mind." I have become a little worried about making a mistake...

I want to merge chapters 1 and 2 as soon as I get home friday evening, but I am not sure how to go about doing it. Can someone tell me really simple like how to get it done?

there's an option at login screen that'll ask for ur key all u have 2 do is enter it, i didnt have this option when i merg'd it but there is an option at the login screen 2 merge the 2 2gether

After entering said key, do you still need to use the start-up discs from the factions box, or are you good to go?

you'll be able 2 use the pre-order key 10 day after the day from the preview event by the end of those 10 days u'll have 2 enter the key from the original factions box if u dont do it before those 10 days they'll lock the char but not delete them for win u do, use the key if u just buy the factions box u'll be able 2 use that key to just get on factions

those big downloads during the events were most of the Factions going onto your hard drive just waiting for the key to go.

discs are to speed up a fresh install but not needed

I know the old way involved logging in to the character screen and adding the key through an options menu, but they added a new interface (I hope you can do it the old way as well)

there are really only 2 options, at login screen there is a button for create new acct or add new access key click on it, next screen has 2 options, either you add your acct login for adding key to existing acct OR you create a new account. Sounds pretty straightforward to me.