This is a task that should be fairly straightfoward, however there are a few confusing "traps" set by the software...
If you want to merge 2 topics, go to your Moderator panel while you are in the relevant forum (not when you are in a relevant topic looking at a post, but one level up.
You should then see the various topics set out. Now imagine I wanted to merge the topic "Test" into the topic "Forum Intro Thread" (in other words, you want to make the topic "Test" part of the topic "Forum Intro Thread" not vice versa). The first thing to do is to mark the box next to "Test" (as shown above) then select "Merge" from the options below (as shown) and click submit.
You will then be presented with your next screen which will look as follows:
You will be tempted the check the box next to "Forum Intro Thread". Do not. This won't work. Instead, you will see "[Select for merge]" before the "Forum Intro Thread" title. Click there (as shown above).
You will then be presented with a confirmation screen. Click "yes" and you're done!
