First, don't panic. There are more steps for dealing with new NHLs than there are for regular National Register listings.
There are two methods by which NHLs are made known to the public. Typically, the first indication of them is via a press release from the office of the US Interior Secretary. This is a dated documented typically saying "Secretary Whoever is pleased to announce" a bunch of new listings, with some background on them. The date of this document is NOT the actual date that the landmarks were designated. Those are found in the National Park Service Weekly Action Lists. These documents, also dated, show what "office actions" were taken by the Park Service with respect to NRHP and NHL listings. The NHL listing designations actions are often not listed until well after the DOI press release, and even longer than the date of the actual office action, which usually took place a month or so before the press release. The Weekly Action Lists include things that the DOI press release does not, including the formal names of the listings, the date of the office action, and the NRIS refnum associated with that action. For previously listed properties, the refnum may be an old refnum, or it may be an entirely new one.
If an article on the subject exists, beware that someone else may already have made a subset of the needed changes to the article. Here are all of the changes you should make:
If the subject has its own category on Commons, you should add it to the appropriate "National Historic Landmarks in X" category. Also add {{NRHP|refnum}} near the top of the category page, for all of the subject's refnums.
If the subject does not have a Commons category, but has more than 2-3 pictures, consider adding such a category.
Someone may already have added a subject to the relevant NHL state or city list. The easiest way to do this is to copy the {{ NRHP row}} from the county list, and then make some modifications. This is sometimes done incorrectly, so there are a number of things to check:
First, don't panic. There are more steps for dealing with new NHLs than there are for regular National Register listings.
There are two methods by which NHLs are made known to the public. Typically, the first indication of them is via a press release from the office of the US Interior Secretary. This is a dated documented typically saying "Secretary Whoever is pleased to announce" a bunch of new listings, with some background on them. The date of this document is NOT the actual date that the landmarks were designated. Those are found in the National Park Service Weekly Action Lists. These documents, also dated, show what "office actions" were taken by the Park Service with respect to NRHP and NHL listings. The NHL listing designations actions are often not listed until well after the DOI press release, and even longer than the date of the actual office action, which usually took place a month or so before the press release. The Weekly Action Lists include things that the DOI press release does not, including the formal names of the listings, the date of the office action, and the NRIS refnum associated with that action. For previously listed properties, the refnum may be an old refnum, or it may be an entirely new one.
If an article on the subject exists, beware that someone else may already have made a subset of the needed changes to the article. Here are all of the changes you should make:
If the subject has its own category on Commons, you should add it to the appropriate "National Historic Landmarks in X" category. Also add {{NRHP|refnum}} near the top of the category page, for all of the subject's refnums.
If the subject does not have a Commons category, but has more than 2-3 pictures, consider adding such a category.
Someone may already have added a subject to the relevant NHL state or city list. The easiest way to do this is to copy the {{ NRHP row}} from the county list, and then make some modifications. This is sometimes done incorrectly, so there are a number of things to check: