Questions about forum. php on the discuz forum homepage

The discuz forum homepage jumps to forum. php. I have installed a forum in the bbs subdirectory of my website. why do I jump to forum. php every time I access the bbs homepage?
I installed a forum in the bbs subdirectory of my website.
Www.abc.com/bbs/ will jump to www.abc.com/bbs/forum.php
The key is that I set the default homepage. no matter which file is set, it will jump to forum. php, which is strange.
I cannot set an application domain name in the background. which one can explain? I hope someone familiar with DZ source code can explain it. Share:
------ Solution --------------------
Forum. php should be the DZ forum homepage. I have read this php before to modify the DZ homepage style. it is called by many php first-level combinations and is complex.
------ Solution --------------------
Index.html jumps to forum by default.
1. modify the forum file name
2, or forum write jump code
3. The background address of the forum has the option to set the homepage to another page. Currently, php has not published any videos for the smart podcast. Therefore, we recommend that you modify the settings so that you cannot provide videos to teach you.