Add the template to the "external links" section of the article to create a link to the appropriate page listing associated archival material at the UK National Register of Archives (NRA)

To use this template, first search for the NRA page relating to the organization, person, family or place

This will often lead to a list of possible matches. If the one you want (e.g. that for Westminster Abbey) is there, click through to the relevant page. The id is the string with which the URL ends, after ID=, e.g. here O63532. Fill in the template as follows:

{{NRA | id=O63532}}
or, more briefly,
{{NRA | O63532}}
or
{{NRA| id=O63532 | name=Westminster Abbey, everyone's favourite abbey}}
to display a name other than the wikipedia article name