you can make the topic “sticky” or even “super-sticky”
you will see the option “stick to front” beside the date if you have permission to do this, or you can go into Dashboard>topics and select the topic. in the top right meta box you’ll see ‘topic attributes’ and you can change that form normal to sticky or super sticky
it’s not the topic, but to sticky the reply. How?
ok, no equivalent way to the sticky but if you
look at the date/time of the topic
look at the date/time of the first reply
Dashboard>replies and select the reply you want to appear directly under the topic, and select edit.
On the bottom right hand side you’ll see ‘publish’ together with a “published on ” date, change that to be a date/time after the topic, but before the current first reply, ie date/time wise it become the first reply.
Thanks! That should work!