: How do I normalise a URL from a folder to a subdomain? I have a mybb forum hosted at a folder inside my site, which can also be accessed via a subdomain. I would like to configure it so

I have a mybb forum hosted at a folder inside my site, which can also be accessed via a subdomain.
I would like to configure it so that if someone would enter the folder it would automatically be redirected to the subdomain:
www.antinovaordemmundial.com/mybb/
to
forum.antinovaordemmundial.com
Once you enter in the forum using the folder URL, any other link will automaticaly redirect to the subdomain, with the exception of the main page ( forum.antinovaordemmundial.com )

My htaccess is as follows:

# Make this rule the first rewrite rule in your .htaccess!
#RewriteRule ^([^&]*)&(.*)$ forum.antinovaordemmundial.com/? [L,QSA,R=301
RewriteRule ^forum-([0-9]+).html$ forumdisplay.php?fid= [L,QSA]
RewriteRule ^forum-([0-9]+)-page-([0-9]+).html$ forumdisplay.php?fid=&page= [L,QSA]
RewriteRule ^thread-([0-9]+).html$ showthread.php?tid= [L,QSA]
RewriteRule ^thread-([0-9]+)-page-([0-9]+).html$ showthread.php?tid=&page= [L,QSA]
RewriteRule ^thread-([0-9]+)-lastpost.html$ showthread.php?tid=&action=lastpost [L,QSA]
RewriteRule ^thread-([0-9]+)-nextnewest.html$ showthread.php?tid=&action=nextnewest [L,QSA]
RewriteRule ^thread-([0-9]+)-nextoldest.html$ showthread.php?tid=&action=nextoldest [L,QSA]
RewriteRule ^thread-([0-9]+)-newpost.html$ showthread.php?tid=&action=newpost [L,QSA]
RewriteRule ^thread-([0-9]+)-post-([0-9]+).html$ showthread.php?tid=&pid= [L,QSA]
RewriteRule ^post-([0-9]+).html$ showthread.php?pid= [L,QSA]
RewriteRule ^announcement-([0-9]+).html$ announcements.php?aid= [L,QSA]
RewriteRule ^user-([0-9]+).html$ member.php?action=profile&uid= [L,QSA]
RewriteRule ^calendar-([0-9]+).html$ calendar.php?calendar= [L,QSA]
RewriteRule ^calendar-([0-9]+)-year-([0-9]+).html$ calendar.php?action=yearview&calendar=&year= [L,QSA]
RewriteRule ^calendar-([0-9]+)-year-([0-9]+)-month-([0-9]+).html$ calendar.php?calendar=&year=&month= [L,QSA]
RewriteRule ^calendar-([0-9]+)-year-([0-9]+)-month-([0-9]+)-day-([0-9]+).html$ calendar.php?action=dayview&calendar=&year=&month=&day= [L,QSA]
RewriteRule ^calendar-([0-9]+)-week-(n?[0-9]+).html$ calendar.php?action=weekview&calendar=&week= [L,QSA]
RewriteRule ^event-([0-9]+).html$ calendar.php?action=event&eid= [L,QSA]

RewriteRule ^([^&]*)&(.*)$ forum.antinovaordemmundial.com/? [L,QSA,R=301]

RewriteRule ^sitemap-([^./]+).xml$ misc.php?google_seo_sitemap= [L,QSA,NC]

RewriteRule ^Forum-([^./]+)$ forumdisplay.php?google_seo_forum= [L,QSA,NC]

RewriteRule ^Topico-([^./]+)$ showthread.php?google_seo_thread= [L,QSA,NC]

RewriteRule ^Anuncio-([^./]+)$ announcements.php?google_seo_announcement= [L,QSA,NC]

RewriteRule ^Usuario-([^./]+)$ member.php?action=profile&google_seo_user= [L,QSA,NC]

RewriteRule ^Calendario-([^./]+)$ calendar.php?google_seo_calendar= [L,QSA,NC]

RewriteRule ^Evento-([^./]+)$ calendar.php?action=event&google_seo_event= [L,QSA,NC]

ErrorDocument 404 /misc.php?google_seo_error=404
<IfModule mod_env.c>
SetEnv SEO_SUPPORT 1
</IfModule>
</IfModule>