Webform – how do I use Group tokens to prefill values

I need to create a form using Webform to allow members to select dates.  The range of the dates comes from variables stored with each group, as do various other variables such as the form closure date and title.  I’m confused as to how I get to use these tokens in my webform.

I have created my WebForm.  I presume I now need to attach this to a node.  What sort of node?  I have a view which has all of the info I need – How do I use that info?  The content type that has all the info I need is a Group.  Do I need to attach the webform to the Group?

Thanks in advance as I have found WebForm very confusing for prefilling fields!

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