DNS Records for Plesk Sub Domain

[#1]

Apologies if this is dealt with elsewhere. Maybe I'm asking the wrong question in the search window but I can't find what I'm looking for.
I have created a sub domain in Plesk it is forums.bromsgroverfc.co.uk it is still unpopulated and of course typing that into my browser doesn't find it as I don't have the DNS records set up yet.
I intend to use something like SMF, phpBB3 or wordpress in this subdomain. Can someone spell out to me,

• What I have to write in my DNS Records to point at this subdomain.
  How can I upload the software to the sub domain as it appears not to have a directory attached to it. i.e. just the name exists.

The main domain is running Joomla but I want to run the forum as  a separate entity so that none members can sign up and login to the forums.
I know I can raise a ticket and get it done for me but I won't learn from that so I want to do it myself with you wonderful people's help
Thanks in anticipation.
Andy

[#2]

Is <a href="http://community.plus.net/forum/index.php/topic,72408.msg592422.html>this</a> what you're trying to do?
The redirect for a single subdomain would be slightly different:

RewriteEngine On
RewriteCond %{HTTP_HOST} ^forums.bromsgroverfc.co.uk$
RewriteCond %{REQUEST_URI} !^/yourfolder/.*
RewriteRule ^(.*)$ /yourfolder/$1

Gabe
Edit:  See below for an easier way to skin that cat.

[#3]

Hi
Through the Plusnet member center you will need to set up the A Record for forum to point towards the Plesk server that you are on.
The record that will need to be set up, is acvailable in the Plesk control panel, by logging in to Plesk > Click on the domain name > dns settings and look for the record for forum
When uploading the files for your subdomain, you need to upload the files to the following folder:
subdomains/forum/httpdocs
Hope that helps

[#4]

So if I do this in the DNS records:-
Left field   Type   Pri   Right field
www         A      212.56.83.200
typing forum.bromsgroverfc.co.uk should point at the sub domain that I've created in plesk?
Corrected 09.22am

[#5]

Hold it, I think I made a mistake there!
I think it should read
Left field forum.bromsgroverfc.co.uk.
Type A
Right Field 212.56.83.200
Then wait for it to sort itself out???

[#6]

Spot on

[#7]

Thanks Kev, knew you'd be there to help 
Just got to get the webspace upgraded to PAYH extra then I can populate it with SMF (same as this) or phpBB3 not too sure which yet. then get it to see the database. and off we go.