By default in new installations of eZ Publish using the ezwebin or similar packages you will have access to the blog, blog post and comment content classes – there are everything you need to get started with your own blog on eZ Publish.
As I built out this site one of the things I noticed with the blog_post.tpl was that comments were being displayed newest first, in the same manner they are on the eZ Publish website, this seems a little counter-intuitive to me and certainly breaks the design pattern established by most other blogging tools available.
To flip the order of your comments to chronological order, oldest first you can approach this in two different ways. You can modify the fetch that pulls back the comments and sort_by the published date, which is what happens by default, you just need to change the ascending/descending option.
The alternative is to accept the default fetch if that is beyond your knowledge and modify the template using the reverse operator to flip the resulting array from your fetch.
I have posted an example below of how this could be done.
{foreach $comments|reverse() as $comment}
{node_view_gui view='line' content_node=$comment}
{/foreach}
I haven’t had a chance yet to run performance tests on each implementation although I believe that the modified fetch function will be faster than array reverse within template code. Over the coming weeks I will have a chance to confirm this.