Just follow the wiki step by step sticking to the version you want, and in any case, do not mix both versions.
(Start over all the times you need, eventually you'll learn to do it easily without the wiki)
If you are talking about Blizzard's trial account it is all the same it is still the full version of world of warcraft client 7.2.0 it just means until you pay for it you only get a trial account the client is still the full version and is complete if that is what you mean.