The exact procedure for installing a new add-on will be directed by the creator of that add-on. However, in general, the procedure will be as follows:
Download the add-on and unzip it.
Upload the add-ons files into your XenForo installation. This will usually create a new directory within the library/ directory in your XenForo installation. In general, this shouldn’t overwrite any existing files.
From your control panel, go to the "install add-on" page. The add-on will have provided an XML file somewhere within it. Upload that file here and submit the form.
many times users put link of other thread in them post so it was ht tp://************/forum/showthread.php?t=xxxx
After imported from vb i need to change these links to ht tp://************/forum/index.php?threads/xxxx
Ok but you should know that if you do this this way, any links in posts that are not to your own forum but follow that same scheme will be broken.
Realistically to do this right I would need a full link including your forum's domain.
If you are absolutely positive that no other links in your forum go to a vb based forum outside of your own than I can give you an expression that will work as you asked, otherwise I will need to capture more than just the part you posted.
If that is what you need to do...but it will not change the data in the posts...they will still display incorrect links to your forum even if they redirect once clicked on.
I have never had a vb forum to import so I really can't tell you based on that fact...your best bet would be to ask @Mike about that but if it were me and I did import a forum I would assume the redirection script would be used to redirect inbound traffic to your site to the appropriate places and I would still replace the text in posts that referrance my own forum so that everything looked clean and right.