Question about WP install settings when changing site to new domain name?

I'm currently trying to move my site from a test domain to the live one. I followed the step-by-step instructions I found in the support area here (though I can't find the article right now to point to what I was reading last night) but it's the one where someone has laid out the whole process. I followed the instructions but unfortunately it didn't work using the basic Export Tool, which is weird because I don't have anything complicated on my site (no posts etc just basic pages) so I though it should be easy.

I think I know where I might have gone wrong - in the instructions it says to create a new install of WP on the new domain. When I did the 5 minute install, when it asks you for the database info should I have used the old mySQL database information or a new one? I was a little scared to use the old one because I thought it might override something on the test site (which I need to be able to see if I need to rebuild it), but logically I know if the old one isn't linked then how can the information come through? If I can't use the old one, then the mySQL backup that I did - how do I import/link that to the new site?

And also when I'm doing the new WP install on the new domain, should I install the plugins I'm using before I import the old site? The first time I did it without and the 2nd time with - still not working but like I said above I think I've done the mySQL part wrong so that's the problem.... but thought I should check on the plugin info as well seeing as I'm going to have to start again anyway. I've tried moving it about 10 times already and then gave up and was like fine I'll rebuild it on the new site, shouldn't take me long. After an all-nighter I've realised it's going to take me days to rebuild so I really need to shift the one I've already done.

Any help would be hugely appreciated :slight_smile: