The article details someone’s campaign ideas, using 6mm Greek armies. It mentions Simple Campaigning, a Society of Ancients publication, which I own and thought well worth a read. It also mentions Setting up a Wargames Campaign. However, I’d say it wasn’t a detailed article, so wouldn’t give you an instant DBA campaign system.
However, one year later in the May/June 2019 Slingshot (which I mistakenly consulted first, having misread wyvern’s post) there IS an article with a DBA v3 specific campaign system for Viking age British Isles - well written, and with the relevant tables, charts and army lists to play a full campaign with DBA.