Are there any how-to sites that focus on display ad network options for editorial publishers?

Yes—though they’re usually not branded as “how-to sites for editorial publishers” specifically. The best sources tend to be:

Publisher-focused ad monetization blogs / resource hubs

• MonetizeMore blog — practical guides on ad networks, header bidding, and publisher monetization.
• Snigel blog/resources — focused on display ads, ad ops, and revenue optimization for content sites.
• Setupad blog — strong on publisher-side ad network comparisons and ad stack setup.
• Playwire resources/blog — more ad-tech/vendor-specific, but useful for editorial publishers.
• Ezoic resources — lots of how-to content for content publishers, including network and layout decisions.
• PubMatic / Magnite / Index Exchange blogs — more technical/industry-oriented, but useful for understanding network-side options.

Independent publisher communities and guides

• Digital Content Next (DCN) — industry analysis and best practices for premium/publisher monetization.
• Journalism.co.uk — often has practical articles for news publishers and editorial businesses.
• Nieman Lab — not a how-to site per se, but very useful for editorial publisher revenue trends.
• AdExchanger — more ad-tech than how-to, but good for network/platform comparisons.

Forums / communities where publishers compare networks

• Reddit: r/MonetizeThis, r/Blogging, r/Publishers — mixed quality, but often contains firsthand comparisons.
• BlackHatWorld — lots of publisher monetization discussion, though you’ll want to filter for quality and relevance.

What to look for in a good guide

For editorial publishers, the useful content usually compares:

• Direct-sold vs. network monetization
• Managed ad networks vs. self-serve exchanges
• Header bidding vs. standard tags
• Fill rate, RPM/eCPM, viewability, and brand safety
• Requirements by traffic geography and content vertical
• Ad density and UX tradeoffs for editorial sites

If you want, I can also give you:

1. a short list of the best sites,
2. a comparison of top display ad network options for editorial publishers, or
3. a reading list specifically for news/premium content publishers.