I finally managed to import almost all of the old image board threads; some of them had corrupted jpgs, so I couldn't recreate the thumbnails and have been partially/totally lost. I'll repost from scratch the ones that I had created, and I'm sorry for the other ones.
I think the new image board is very straightforward to use, but let me explain some points that might not be obvious.
- The post deletion system is 4chan-alike. When you post a thread/comment, you can specify a password. You can then select your post, input your password again in the form at the bottom of the thread, and use the delete button. If you are the thread creator, you can input the password of the first post and use the delete thread button (without having to manually select the posts). If no password is entered while posting, the post is undeletable.
- You can add tags to every thread. While viewing a thread, on the left column, enter some significant tags for the thread (i.e. for a K-ON thread, 'k-on', 'music', 'school girls', 'slice of life', 'kyoani'). Everyone can delete the tags and enter new ones. The administrators can approve the single tags, so that the delete icon will disappear from them. Once the thread has some tags, you can use the search function on the image board page and it will appear in the search results.