How does PrintDOCs work with the Koha ILL module?
The Koha ILL module checks availability of articles in PrintDOCs. It checks against ISSNs, so only indicates that the journal, in which the article has been published, is listed in PrintDOCs.
If the journal is listed. this screen will display:

To load-balance, the holdings in libraries in your regional INC network are shown first. There may not be any holdings in your region. The year of the article is displayed and holdings which potentially can supply the article, highlighted. Check to see if the holding has any missing volumes or issues. Do these prevent the library supplying the article.
Click the Show request details toggle to show the citation. Click the Show INC network matrix toggle to show the order in which to approach libraries outside your region.
If libraries in your region do not have holdings for the title, or do not cover the volume and issue you need, toggle on the INC network matrix and work your way through your region's rota, typing the initial letter of the network as necessary to find a library which can supply. Alternatively, delete the INC Network to show all holdings.
If there are no holdings for a title in your region, you will see:

Just toggle on the INC network matrix and work your way through your region's rota. If there are no holdings at any library, no holdings will be highlighted.
Once you're happy that a library can supply, click the Request this item button for the library's holding.
Confirm the request and then confirm you definitely want to send the request.